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REVIEW OF HERBICIDE RESEARCH ON SESAME (Sesamum indicum L.)

D. Ray Langham James Grichar Peter Dotray August 2007

Version 1

This is a living document that will be updated on the internet as more information is gathered on a quarterly basis. The summary document will be updated more frequently.

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Across the globe, wherever sesame is grown, there has been an increasing use of herbicides. Up until now, sesame has been a manual crop with hand-weeding and hoeing for millennia. The purpose of this paper is to provide researchers insight for a starting point to determine which herbicides will be best for trials in their areas. There are some herbicides that are more promising than others, and there is no sense in wasting scarce time and research funds trying herbicides that have already proven to be unusable for sesame. There are many variants of the word preemergence as it pertains to herbicide usage in the world literature. In this paper the terms and abbreviations have been standardized as follows: · Herbicides applied preplant with no incorporation (PREPLANT) · Herbicides applied preplant incorporated (PPI) · Preemergence (PRE) ­ Herbicides applied after planting and before weed or crop emergence. · Postemergence (POST) ­ There are two types of herbicide application: over the top (OTT) of sesame and directed (DIR) at the base of the sesame. There is a POST DIR where the herbicide is sprayed between the rows and does not touch the sesame, but unless specified all the POST DIR research discussed below implies spraying on to the base of sesame. Sesame is one of the oldest crops known to man. There are archeological remnants of sesame dating 5,500 BP in the Harappa Valley in the Indian subcontinent (Bedigian and Harlan 1986). Bedigian et al. (1985) have shown that sesame originated on the Indian subcontinent and spread to other parts of Asia and Africa thousands of years ago. From ancient times to modern times, sesame has required considerable manual labor from planting through harvest. Over 99% of the sesame today is still harvested manually. In several international meetings in the 1990s, the first author made a very controversial prediction: unless sesame is mechanized in the next 20-25 years, its world production will decrease significantly. Without mechanization, sesame will only persist in those niches where no other more suitable crop can be grown. Since that prediction, production and world trade has continued to increase. However, the trends are clear. The availability of manual labor continues to decline even in countries such as India. Roundup Ready crops are accelerating this decline. Sesame has disappeared in traditional growing areas that have become mechanized such as Japan and the Obregon area of Mexico, and is disappearing in Gujarat in India where mechanization is accelerating. Korea, Thailand, and China are developing equipment that can operate in small fields and mechanization will be pervasive faster than in the US and Europe. There has been considerable progress in mechanizing the crop by the development of nondehiscent capsules (Langham and Wiemers 2002) that hold the seed until combining and then release the seed within the combine with minimum threshing. In addition, the growth habit of phenotypes have been changed to more readily feed into combines. The one area of best management practices for sesame that is still in development is the use of herbicides. Several agronomic practices have reduced the need for herbicides in dry areas. Cleaning the fields prior to planting and then cultivation between rows has helped reduce weeds until the crop canopies. In areas that have early rainfall, herbicides are a must. In addition, the trend is to minimum and no-till practices which will require both PRE and POST herbicides. In many areas where Roundup Ready crops are predominant, there are no longer hoe crews to manually clean the fields. One of the more difficult problems in planting sesame is that the seeds are small and need to be placed precisely in the soil. They cannot be so deep that the cotyledons never reach the surface, and yet they cannot be so shallow that the moisture around the seed is lost. Once the cotyledons emerge they are small compared to other crops and do not grow as fast. This slow development

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is compounded by the nature of the drought resistance of sesame in that it will partition a large portion of photosynthetic resources to create more root mass to penetrate the soil as quickly as possible to follow the moisture. Figure 1 shows how in the first 30 days the plants reach about 28 cm in height and yet will double to 60 cm in the next 11 days, triple to 90 cm in the following 8 days, and quadruple to 120 cm in the following 9 days. At this point the sesame will begin to canopy. Depending on row spacing and phenotype, mechanization of sesame requires good weed control for 50 to 60 days after planting. Figure 1. Rate of growth of 3 US varieties in adjacent plots under irrigation in South Texas.

210 180 150 Plant height (cm) 120 90 60 30 0 0 10 20 30 40 50 60 70 80 90 100 Days from planting

S24 S26 S29

As with other crops, weeds in sesame will reduce yields by using moisture and fertility and in some cases blocking sunlight from the sesame. The constraint imposed by weeds on high yield is sesame has been well documented. Balyan (1993) and Singh et al. (1992) reported weed-induced yield reductions up to 135% and a need for a critical weed-free period up to 50 days after planting. Eagleton et al. (1987) recorded a weed biomass 6 times that of sesame 48 days after planting and Bennett (1993) reported weed biomass 1.3 times that of sesame 42 days after planting. In mechanical harvest, there is an additional window of weed control that is important. The major form of weed control after the first 40-50 days of planting is the sesame canopy which blocks out light. At about 60 days after planting, current sesame varieties begin losing the leaves under the canopy where there is no light. As the plants mature, they self-defoliate and leaves are gone at about 100 days after planting. It takes 40-50 days from the time that the plants lose all their leaves until the sesame is dry enough to combine. The leaves are a major part of the sunblocking canopy, and in addition, as the weight of the leaves is lost, the branches become more erect letting even more light in. With fall rains there may be a new flush of weeds, particularly fast growing grasses. These late weeds can be controlled in four ways: applying POST DIR herbicides that have a long residual control; having narrower row spacing; planting the rows north/south so that there is light to the ground only at mid-day; and using harvest aids to shorten the sesame drying period and which also kill and dry weeds. Mechanically harvested non-dehiscent varieties present another problem that is not present in manual harvest which comprises 99% of all sesame harvested in the world. If there are weeds in manual harvest, only the sesame plants are cut and placed in the shocks. However, in mechanical harvest, sesame and weeds are cut together. In Venezuela, a binder cuts the sesame and weeds

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together while they are still green, and this is not a big problem because the weeds dry down at the same time as the sesame. The only concern is that a high population of weeds may delay the combining in that the leaves of the weeds may envelop plants and trap moisture or thicker stem weeds such as pigweed (Amaranthus) will take longer to dry down. In direct combining, the weeds can be a big problem in that they are normally green and add moisture to the combine bin. There are many cases where the sesame seeds are dry and weed seeds are not. Thick stems can add moisture, but the major problem is with weed seeds. Since it is logistically difficult to scalp off the weed seeds at harvest, moisture from the weeds will transfer to sesame seeds. Sesame is 50% oil and needs to be harvested at 6% moisture or below in order to be handled in lots of 25 tons in trucks and in 2,000 ton silos. High moisture under these conditions can lead to heating and ruining of the seed. A second concern is that mechanically harvested sesame moves through a series of augers from the combine screen, to the combine bin, to the truck, to the silo, to the cleaning equipment, and within the cleaning process. Moist sesame can be damaged by this movement forming free fatty acids and leading to spoiling. The final problem is the small size of the sesame seed which is similar to the size of many weed seeds. In the use of oil, weed seeds within the sesame samples is not as critical unless they are toxic. However, a large percentage of sesame is used in edible markets that require 99.99% purity. There are seeds such as johnsongrass (Sorghum halepense) that would seemingly be easy to clean out because of their size and shape, and yet the johnsongrass seed go end first through the round holes and are difficult to separate in gravity tables because they have a similar specific gravity to sesame. In decortication of the seed for bakery products and tahini, the seed from mintweed (Salvia reflexa) causes a unique problem. When the mintweed seed is hydrated, the surface forms a gelatinous substance that will stick all the sesame seeds around it forming balls. Kochia (Kochia scoparia) and grass seeds are other weeds that are difficult to clean out of sesame. Any weed seed that is in large percentage in sesame, is difficult to clean out, no matter the size and specific gravity, without having to slow down the processing or reprocessing. In Japan, purity needs to be 100% with processors having to pay claims to customers that find anything other than pure sesame seeds. Below it will be seen that there have been conflicting results with a few herbicides, and it is difficult to sort out why some herbicides work in one country and do not work in another country. In some cases, in the same location they work one year but do not work in the next year. In some of the materials it is evident that the method of application and the dosage make a difference. Martin (1995) felt that rainfall amounts during germination and establishment can markedly affect herbicide toxicity to sesame, a possible factor in the reported erratic behavior of many herbicides. Sesame is a survivor crop. It has been planted for over 7,500 years in Asia and Africa in very poor growing conditions. In parts of Thailand (W. Wongyai, 2003, pers.commun.) farmers broadcast the seed and come back at the end of the season and see which crop has won ­ the sesame or the weeds. More often than not, the sesame wins. Cultivars in those areas are tall and have very long internodes and can get up above weeds. Many herbicides will set sesame back, but few will kill it off. In many of the tests below, it will be seen with some herbicides that even with severe stand reduction, sesame yields are good because the plants can compensate for open space by putting out branches with capsules. This review of the research and growing guide recommendations will focus on the effects of the herbicides on the sesame because the weeds in each country are different requiring different solutions. In some of the work the amount of weed pressure is not described, and thus it is not known if the yields of the checks are affected by weeds. In other trials there are two checks ­ one with no weed control and one with weed control. In many of the weeded checks the yields are lower because workers have difficulty in differentiating the sesame from the weed seedlings

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resulting in lower sesame plant stands. This paper will also include active ingredients that did not work for sesame. Some of the herbicides cited are very old and out of production [OP]; some have been banned because of toxicity to the environment; and others are no longer used because so much chemical has to be applied to be effective. However, they are still included because they may provide some insight to other related chemicals that could be tested. In some testing in the US where multiple varieties were used, there were differences between the varieties. Some of the clues have not been followed up because the moving baselines of new varieties has been fast, and the emphasis has always been placed on the use of the most recent released variety to use in herbicide evaluations. More work needs to be done in this area; particularly to determine whether a specific genotype may have more resistance to a particular herbicide. A review of sesame herbicide information from 21 countries has shown that there are 14 herbicides that are used in commercial sesame fields somewhere in the world. Some of these herbicides are out of production in the US. There are 4 additional herbicides that have potential for use in commercial fields but need more research. Table 1 shows the active ingredients of these 18 herbicides with the most common name in the US sesame growing area. Table 1. Most promising herbicides for use on sesame.

Use Commercial fields PRE Alachlor (Intrro) Diuron (Direx) Fluchloralin (Basalin) Fluometuron (Cotoran) Glyphosate (Roundup) Linuron (Lorox) Metobromuron + Metolachlor (Galex) Metolachlor (Dual) Pendimethalin (Prowl) Trifluralin (Treflan) Clopyralid (Lontrel) Diuron + linuron (Layby Pro) POST OTT Clethodim (Select) Diuron (Direx) Fluazifop-P (Fusilade) Haloxyfop (Verdict) Sethoxydim (Poast) POST DIR1 Diuron (Direx) Glyphosate2 (Roundup)

Diuron + linuron (Layby Pro) Flumioxazin (Valor) Glufosinate (Ignite) Glyphosate (Roundup) Prometryn (Caparol) 1 Initial testing indicates that the stage of the sesame, the height of the plant, and the height of application are critical and need more testing. 2 Only between rows ­ not directed on stems of sesame.

Potential use

Pendimethalin (Prowl) Metolachlor (Dual)

There are many PRE herbicides that have been successfully used in the world: alachlor, diuron, fluchloralin, fluometuron, linuron, metobromuron + metolachlor, metolachlor, pendimethalin and trifluralin. However, herbicides act differently under certain environmental conditions which include variability in soil, temperature, humidity, rainfall, and under different methods and timing of application. Pendimethalin and trifluralin are particularly difficult to use with results ranging from great weed control with no damage to the sesame to little or no sesame stand. Poor sesame stands with the use of pendimethalin or trifluralin have resulted from incorporating either of the herbicides too deep. Since sesame is planted shallow, it is difficult to properly incorporate the dinitroaniline herbicides effectively and not have the herbicides come in contact with the sesame

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seed or roots. It is important to read the literature and to try these herbicides experimentally before applying them in farmer fields. As Grichar et al. (2001b) pointed out, little or no research has been done on the use of POST herbicides in sesame. Most of the herbicide work has been at crop establishment. From initial work done in the US in Arizona, several POST OTT grass herbicides have done a very good job controlling grasses and not damaging the sesame. The grass herbicides, fluazifop-P, haloxyfop, and sethoxydim have been used successfully in many parts of the world. More recently, clethodim has proven equally good controlling both annual and perennial grasses (particularly johnsongrass) and not damaging sesame. There is a label for clethodim (Select Max) use in sesame which allows spraying in all phases expect flowering. Concerns have been raised on the use of clethodim after extensive Roundup Ready spraying. Sesame capsule inhibition has been noted when glyphosate carryover has been noted in spray tanks that have been used to spray clethodim. The cleaning of spray tanks after each herbicide use is vital. Bennett (1998) found that alternating of grass and broadleaf crops in Queensland, Australia, helped in reducing weed populations since broadleaf weeds could be easily controlled in the grass crops and the grass weeds could be controlled in the sesame crop. However, this method is not as effective in the US as would be hoped for. In many areas where either corn (Zea mays) or sorghum (Sorghum bicolor) have been grown the previous summer, broadleaf weeds appear late in the season and often are not controlled until after they have gone to seed. Many of these problems result from the inability to disk the weeds mechanically due to lack of soil moisture. In growing wheat (Triticum aestivum) in the winter and spring prior to sesame, there are two problems: (1) there can be residues from broadleaf herbicides applied to the wheat in the spring that are toxic to sesame, and (2) there are many broadleaf weeds that will not germinate until the warm summer temperatures. In all areas there are winter weeds that will not germinate until the sesame plants lose their leaves. To date there is no POST OTT broadleaf herbicide that will control the weeds without damaging the sesame. There are products such as alachlor and metolachlor that will not damage sesame when applied PRE, will not kill any emerged weeds, but will provide some residual control. In the case of herbicides such as diuron, sesame will recover, but the farmer must look at damaged sesame for about 10 days after herbicide application and have faith that the sesame will recover. In some of the research, even more damage to the sesame from other herbicides with good weed control has proven to produce higher yield because of the loss of production to weeds. However, it is very difficult for a grower to see the amount of sesame damage even knowing that the sesame will recover. Starting in 2003, work has been done on POST DIR herbicides with and without the use of hooded sprayers. This work is very encouraging; however, there are many cropping patterns that preclude the use of hooded sprayers. There is a label for glyphosate (RT3) which allows spraying with wiper applicators or hooded sprayers between sesame rows. While this does not kill weeds in the sesame seed line, it helps, particularly with vining weeds such as morningglory than spread across the rows. In the case of Amaranthus which quickly becomes taller that the sesame, wiper applicators using glyphosate have been very successful as long as the glyphosate does not leak on to the sesame. There is one positive aspect from the Roundup Ready crops. In the US, there is much less weed pressure on sesame when a Roundup Ready crop is grown the previous summer because in many instances the winters are too cold to allow germination of troublesome summer weeds. However, in warmer parts of the world, uncontrolled weeds will go to seed. In these areas, glyphosate is so effective in controlling weeds in those crops, that farmers are not concerned with a build-up of weed seeds in the soil between crops. On the other hand there are very

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conscientious farmers that are very aggressive in keeping the weeds from going to seed even after crop harvest. Therefore, in those areas, there are few weed seeds in the upper soil profile and manual crews easily handle carry over seed that may come in from birds and wind. There is one group of broadleaf weeds that continues to affect sesame ­ the hard seeded broadleaves (e.g., morningglory [Ipomoea spp.]) that come up in flushes after a rainfall or irrigation event and after sesame canopy formation. These weeds can continue growing under weak light conditions, climb the sesame plants to the top of the canopy, and when they reach the light, greatly expand their infestation. As soon as they reach light, their leaf size increases dramatically. In high populations, these twining weeds can push down the sesame and cause problems at harvest in that it is difficult to separate adjacent rows of sesame at the edge of the combine. Many farmers go into these areas with glyphosate and sacrifice the sesame to keep the problem from spreading in future years. However, the best control for this type of weed is to use glyphosate in hooded sprayers while the plants are growing across the space between the sesame seed lines. One of the major problems in using POST DIR herbicides will be the timing of the application and the height of the application on the sesame stem as related to the height of the plant. When there are dominant and minor plants in a high sesame population, the use of herbicides such as glyphosate kill the minor plants which are smaller in size but the dominant plants which are taller are not killed. In waiting for the sesame to get tall enough to spray, weeds also get tall and herbicides may not kill the weeds. In reviewing the POST research, it is sometimes difficult to understand exactly at what stage of growth the herbicide was applied. Many of the documents will cite the number of days after planting or the height of the plants. However, there are many differences in the cultivars of the world in terms of number of days in each stage and in the heights of the plants in each stage as shown in Table 2. Table 2. Range and mean of number of days in phases for all Sesaco germplasm. Days from planting Phase length (days) Phase Range Mean Range Mean Vegetative 29-59 42 29-59 42 Reproductive 56-116 89 16-70 47 Ripening 77-140 108 (14)z-54 11 Drying 102-181 150 11-57 38 z In some lines, there are dry capsules above green leaves while the upper part of the plant is still flowering creating a negative range. In order to standardize terminology, a phenology chart has been developed to specify the beginning and end points of the stages (Langham 2007). Table 3 summarizes the phenology. Table 3. Phases and stages of sesame. Stage/Phase Vegetative Germination Seedling Juvenile Pre-reproductive Abbrev VG GR SD JV PP End point of stage Emergence 3rd pair true leaf length = 2nd First buds 50% open flowers DAP a 0-5 6-25 26-37 38-44 No. weeks 131+ 1-

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Reproductive Early bloom Mid bloom Late bloom

RP EB MB LB

Ripening RI 91-106 Drying DR Full maturity FM All seed mature 107-112 Initial drydown ID 1st dry capsules 113-126 Late drydown LD Full drydown 127-146 a DAP = days after planting. These numbers are based on S26 in 2004 Uvalde, Texas, under irrigation.

5 node pairs of capsules Branches/minor plants stop flowering 90% of plants with no open flowers Physiological maturity (PM)

45-52 53-81 82-90

1 4 1+ 2+ 12 3

Although the main thrust of this paper has been the controlling of weeds in sesame, there is always a concern as to whether sesame will become a weed in other crops used in rotation with sesame. There are many PREPLANT and PRE herbicides used in other crops that will prevent sesame from germinating. To date there is only one herbicide that will kill the sesame consistently from the juvenile stage on ­ glyphosate. However, in some experiments prometryn, flumioxazin, imazapic, trifloxysulfuron, mesotrione, flumetsulam, and foransulam have virtually wiped out the sesame. Most POST OTT herbicides set back the sesame enough for the crop to canopy over the sesame. Until the advent of Roundup Ready cotton (Gossypium hirsutum), sesame could become a problem weed. Under normal planting conditions, cotton germinates about 5 degrees cooler than sesame and has a faster growth curve in the first 30 days than sesame. Cotton planted on time rarely had sesame as a weed. The problem was primarily in areas where cotton planting was delayed for integrated pest management reasons. When there was a sesame weed issue, most of the previous cotton herbicides would set the sesame back, but would not kill it. As long as the stand of cotton was good, the cotton would outgrow and canopy the sesame, but in a low population, the sesame would persist. However, sesame was never a problem in the harvest of the cotton. With Roundup Ready cotton, the situation is reversed in that cotton can now be a weed in sesame. Sesame could be a problem in peanuts (Arachis hypogaea), but with the new peanut herbicides such as Cadre (imazapic) or Pursuit (imazethapyr), sesame has not been a problem. Sesame was never a problem in monocot crops such as corn, sorghum, and cereals because there are many good broadleaf herbicides that would control sesame. Theoretically, sesame could be a weed in many vegetable crops, but with a wide range of herbicides approved for those crops and the usual presence of manual labor, sesame has not been a problem in any one vegetable crop to date. In all of the testing, there is no magic herbicide that does not affect sesame under some condition; however, it is clear that without weed control, sesame cannot produce economical yields. Therefore, some damage must be acceptable and with this minimal damage to the sesame, many herbicides have produced excellent economic yields. In the 1920s, Iowa farmers used to say that they plant 3 kernels of corn, "One for the worm, one for the crow, and one for me." Perhaps, in this century sesame farmers will need to plant extra sesame seed, "Some for the herbicide, and most for me." From the paragraphs above, it might appear that control of weeds is the most important part of growing sesame. There are millions of non-mechanized and hundreds of thousands of

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mechanized hectares of sesame grown every year with good economic return and minimum loss to weeds. However, improved weed control systems will contribute to increased net returns of the crop. The major strategy that is being considered is to use a PRE herbicide that has residual control and will hold the weeds down for about 3-4 weeks, then use a POST DIR herbicide that will control small weeds and provide residual control of weeds that have not germinated. The following summarizes the herbicide research broken down alphabetically by active ingredient, and chronologically within active ingredient. Appendix 1 organizes the same information by country. Some researchers use the name of the active ingredient instead of trade names, and others use the trade name instead of the active ingredient. In the cases where they use only the trade name, the authors have added the active ingredient. Appendix 2 provides a crossreference tables arranged alphabetical by trade name. Table 4 provides a quick index to the page of the active ingredient and a quick evaluation. In the evaluation the following abbreviations are used: · Com = commercial (used commercially in at least one country) · Pot = potential (potential to use commercially) · Sel = selective to sesame (does not damage sesame) · SSel = somewhat selective to sesame (some damage to sesame, but helps) · Mix = mixed results · Tox = toxic (substantial reduction of production) · STox = somewhat toxic (enough reduction that probably cannot be used) · NER = not enough research Table 4. Herbicides used in sesame in alphabetical order by active ingredient

Page 11 12 14 22 22 23 23 24 24 25 25 27 Active ingredient 2,4D-B Acifluorfen Alachlor Allidochlor (CDAA) Ametryn Amiprophosmethyl Asulam Atrazine Benefin Benfuresate Bensulide Bentazon Trade name Butyrac Blazer Alanox, Intrro Lasso, Lazo Randox Gesapax Bay-NTN 6867 MB-9057 Aatrex Balan Cyperal Prefar Adagio, Basagran, Bendioxide, Entry, Leader, Pledge Modown Buctril, Weedex R-120001 Aim Amiben Classic Tenoran Chloro-IPC, Furloe PRE Tox Com Mix Tox Tox SSel Tox Tox Tox Sel POST ott Tox Tox Pot POST dir Pot Harvest Aid

Tox

Tox

30 30 33 34 34 36 36 37

Bifenox Bromoxynil Carbuthioate Carfentrazone Chloramben Chlorimuron Chloroxuron Chlorpropham (CIPC)

Tox Tox STox Sel Mix Tox Tox Mix NER

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Page 40 40 40 41 43 44 44 45 45 45 46 46 48 48 49 50 50 51 51 51 55 55 59 59 60 62 62 64 65 65 66 67 70 73 73 75 75

Active ingredient Chlorsulfuron Chlorsulfuron + Metsulfuron methyl Chorthal-dimethyl Clethodim Clomazone Clopyralid Cloransulam Dicamba Dichlobenil Dichlormate Diclofop Diclosulam Diethatyl Diethylacetanilide Diflufenican Diflufenzopyr Dimethenamid Dinitramine Dinoseb Diphenamid Diquat Diuron Endothall EPTC Ethalfluralin Fenoxaprop Fluazifop-P Fluchloralin Flufenacet Flufenacet + metribuzin Flumetsulam Flumioxazin Fluometuron Fluorodifen Fomesafen Foramsulfuron + iodosulfuron Glufosinate Glyphosate

Trade name Glean Finesse Dacthal, Prothal, Shamrox Select Max Command Lontrel FirstRate Clarity Casoron Hoelin Spider, Strongarm Antor C-10725 Brodal Distinct Frontier Cobex Premerge Dymid, Enide Reglone Direx, Diurol, Karmex Accelerate Eptam Curbit, Sonalan Whip Fusilade Basalin Radius Axiom, Domain Preside Broadstar, Chateau, Sumixoya, Valor Cotoran, Lanex Preforan Flex, Reflex Equip Liberty, Finale, Rely, Ignite, Basta Roundup, RT3, Touchdown, Buccaneer, Durango Verdict Beyond Cadre Pursuit

PRE Mix Mix STox

POST ott

POST dir

Harvest Aid

Com Tox Pot Tox Tox SSel NER Tox SSel SSel STox Mix Tox Tox Sel Com Tox Mix Mix NER Com Tox Tox Tox Tox Com Tox Mix Tox Pot Com Tox Mix NER NER Tox Mix

Tox Tox

Tox

Tox Tox

Sel NER Com Tox Sel

Com

Mix

77 79 80 80 82

Haloxyfop Imazamox Imazapic Imazethapyr

Sel Tox STox Tox Tox

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Page 84 85 87 91 92 92 93 93 94 101 103 103 103 103 105 105 106 106 107 108 108 110 111 111

Active ingredient Isopropalin Lactofen Linuron Mesotrione Methabenthiazuron Methazole Metobromuron Metobromuron + metolachlor S-Metolachlor Metribuzim Metsulfuron Monolinuron Monuron Napropamide Naptalam (NPA) Nicosulfuron Nitralin Nitrofen Norea Norflurazon Oxadiazon Oxasulfuron Oxyfluorfen Paraquat

Trade name Paarlan Cobra Afalon, Lorox Linorox, Teliron Callisto Tribunil Probe Patoran Galex Allfire, Dual Magnum, Medal Lexone, Sencor, Sencorex Ally Afesin Monurex, Telvar Devrinol. Pamid Alanap Accent Planavin Herban Solicam, Zorial Ronstar GCA, Dynam Goal Gramoxone, Gramoxone Inteon, Parazone Tillam Herbadox, Prowl, Stomp Destun Betanal Ecopart Agriflan, Pregard Caparol, Gesagard, Suprend Kerb Ramrod Stam-F-34 Milogard, Milocep, Milo Pro Exceed, Peak ET Lentagram, Tough Staple Matrix Crag Poast, Sertin

PRE Tox

POST ott Tox

POST dir STox Sel

Harvest Aid

Com Tox SSel Mix Com Com Com Tox Mix Mix Sel Mix Tox Mix Mix Tox Mix Tox SSel SSel Sel

Tox Tox

STox Tox Tox Stox

Stox

NER

112 113 119 119 119 120 120 120 127 127 127 128 128 129 130 130 132 133 133

Pebulate Pendimethalin Perfluidone Phenmediphan Piflufen ethyl Proatryne Profluralin Prometryn Pronamide Propachlor Propanil Propazine Prosulfuron Pyraflufen ethyl Pyridate Pyrithiobac Rimsulfuron Sesone Sethoxydim

SSel Com Sel

Sel

Tox SSel Sel Sel Tox Tox Sel SSel Mix Mix

Tox

Sel

Tox Tox Stox Mix Tox Tox Com

Sel

Sel Tox

NER

Tox Sel Mix

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Page 135 135 135 135 136 137 137 138 144

Active ingredient Simazine Sirmate Sufentrazone Sulfonamide Thiobencarb Triasulfuron Trifloxysulfuronsodium Trifluralin Vernolate

Trade name Princep Authority Python Bolero Amber Envoke Treflan, Agriflan Vernam

PRE Tox NER Tox Mix Tox Mix Mix Com Tox

POST ott

POST dir

Harvest Aid

Tox

Tox

2,4DB (Butyrac)

PRE summary: Reduces the germination substantially. In Venezuela, Mazzani (1957) tried several PRE herbicides and found that 2,4D reduced the germination too much. In the US, the first author has made the following observation: · When a farmer used 2,4D-B in a mix with glyphosate as a burndown PRE for a variety trial, the sesame germination was reduced substantially. POST OTT summary: Toxic to sesame with severe stunting and substantial yield loss, but does not kill the sesame. Is highly volatile and drift can affect sesame even when used in adjacent fields. In the US, Culp and McWhorter (1965) cited Tocquigny and Livingston (1953) that MCPA (2,4D) caused slight to severe stunting. However, most of the plants essentially overcame the stunted condition before harvest. In Australia in South Burnett, a grower guide (Sapin et al. 2000) states that sesame will not tolerate 2,4-D. In the US in Texas, Grichar et al. (2001b) conducted POST OTT studies in weed free areas at Yoakum and Uvalde from 1994 to 1997. The varieties used were Sesaco 11, 17, or 18. The herbicides were applied over the top 3-4 wk after planting in Yoakum and 6 wk after planting in Uvalde. Sesame was 30-48 cm in height at the time of application. Planting dates in Yoakum were 26 May 1994, 11 July 1995, 12 July 1996, and 1 July 1997. Planting date in Uvalde was 28 April 1995. In 1995, 2,4DB high rate reduced the stand by 77%. Ratings of stunting (0= no stunting and 100 = total stunting) were done 3 weeks after herbicide application as shown below.

Rate (kg/ha) Check 2,4-DB 2,4-DB LSD (0.05) 0.22 0.45 94 YOA 0 56 75 28 95 UVA 0 35 63 19 95 YOA 0 48 64 12 96 YOA 0 10 40 22 97 YOA 0 39 81 12

2,4-DB stunted the sesame severely particularly at the high rate. The effects on plant height were as follows:

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Rate (kg/ha) Check 2,4-DB 2,4-DB LSD (0.05) 0.22 0.45

94 YOA 91 34 8 25.7 94 YOA 408 15 61 248

95 YOA 110 65 75 32.2 95 UVA 844 578 454 210

96 YOA 71 61 42 23.1 95 YOA 482 260 280 255

97 YOA 74 53 36 16.1 96 YOA 419 264 192 217 97 YOA 501 407 374 NS Avg 531 305 272 % check 57 51

2,4-DB reduced the plant height substantially. The yields were as follows:

Rate (kg/ha) Check 2,4-DB 2,4-DB LSD (0.05) 0.22 0.45

2,4-DB the yield to the point that it cannot be used for sesame. In the US in Texas, Grichar and Langham (2003) conducted a POST OTT test in Batesville. A 5 ft swath of herbicides was sprayed across three rows of five lines leaving 15 ft of each row untouched to allow a direct within row comparison of the effects of the treatments. The herbicides were sprayed over the top in the juvenile stage when the plants were about 18" tall. There was a dual purpose: (1) find herbicides that were selective to sesame and (2) find herbicides that would control volunteer sesame in other crops. In this test, there were no weeds since the main thrust of the study was to look at the effects of the herbicide on the sesame. There were no replications in that the idea was to take the better lines and test them in Grichar et al. (2007). At the end of the ripening phase, the plots were evaluated in terms of percentage production compared to the untouched plants in the same row.

Treatment 2,4D-B Rate 0.5x 1.0x Average S26 30 30 37 S27 50 50 49 S28 30 20 37 S29 40 80 48 132 20 20 31 Average 34 40 40

2,4D-B had less effect on S29 than on the other lines. The 80% production was verified in the field. Overall 2-4D-B reduces production substantially. In the US, the first author has made the following observations: · When 2,4D-B is used along the edges of the field for border weed control, there is injury to the sesame but usually it is not killed. · In a nursery in Oklahoma, 2,4D-B was sprayed on peanuts to the south on a non-windy day. Although the sprayer stayed over 20 m away from the sesame field, there was drift that damaged the sesame close to the peanuts, and there was evidence of drift as much as 100 m into the nursery. The affected plants had twisted stems and did not produce capsules for up to a week. There was more effect on some lines than on others. POST DIR summary: No known research.

ACIFLUORFEN (Blazer)

PRE summary: No known research. POST OTT summary: Toxic to sesame in all but one test with substantial yield reduction. In the one test where yield was higher, there was considerable weed pressure in check.

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In the US in South Texas, Grichar et al. (2001b) conducted POST OTT studies in weed free areas at Yoakum and Uvalde from 1994 to 1997. The varieties used were Sesaco 11, 17, or 18. The herbicides were applied over the top 3-4 wk after planting in Yoakum and 6 wk after planting in Uvalde. Sesame was 30-48 cm in height at the time of application. Planting dates in Yoakum were 26 May 1994, 11 July 1995, 12 July 1996, and 1 July 1997. Planting date in Uvalde was 28 April 1995. In 1995 none of the herbicides reduced stands while in 1997, stands were reduced as follows: acifluorfen low rate 65%. Ratings of stunting (0= no stunting and 100 = total stunting) were done 3 weeks after herbicide application as shown below.

Rate (kg/ha) Check Acifluorfen LSD (0.05) Rate (kg/ha) Check Acifluorfen LSD (0.05) Rate (kg/ha) Check Acifluorfen LSD (0.05) 0.28 0.56 0.28 0.56 0.28 0.56 94 YOA 0 83 89 28 94 YOA 91 7 0 26 94 YOA 408 0 0 248 95 UVA 0 78 65 19 95 YOA 110 69 80 32 95 UVA 844 650 820 210 95 YOA 0 30 43 12 96 YOA 71 41 12 23 95 YOA 482 109 146 255 96 YOA 0 70 83 22 97 YOA 74 34 35 16 96 YOA 419 159 174 217 97 YOA 501 665 548 NS Avg 531 317 338 % check 60 64 97 YOA 0 79 91 12

Acifluorfen stunted the sesame. The effects on plant height (cm) were as follows:

Acifluorfen reduced the plant heights to almost half. The yields (kg/ha) were as follows:

Acifluorfen reduced the stand, stunted the sesame, reduced the height, and lowered the yield by 42%. It does not work as an over the top POST herbicide for sesame. In the US in South Texas, Grichar and Langham (2003) conducted a POST OTT test. A 5 ft swath of herbicides was sprayed across three rows of five lines leaving 15 ft of each row untouched to allow a direct within row comparison of the effects of the treatments. The herbicides were sprayed over the top in the juvenile stage when the plants were about 18" tall. There was a dual purpose: (1) find herbicides that were selective to sesame and (2) find herbicides that would control volunteer sesame in other crops. In this test, there were no weeds since the main thrust of the study was to look at the effects of the herbicide on the sesame. There were no replications in that the idea was to take the better lines and test them in Grichar et al. (2007). At the end of the ripening phase, the plots were evaluated in terms of percentage production compared to the untouched plants in the same row.

Treatment Acifluorfen Rate 0.5x 1.0x Average S26 60 50 37 S27 70 40 49 S28 60 50 37 S29 60 60 48 132 50 40 31 Average 60 48 40

There is still substantial production reduction with acifluorfen, but this was the best broad leaf herbicide in this test. In the US, Grichar and Dotray (2007) conducted POST OTT studies in two locations in Texas (Yoakum and Lubbock) in 2004 and 2005. The herbicides were applied in the pre-reproductive

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stage when the plants were about 60 cm tall. The Lubbock trials were virtually weed free while there were weeds in the Yoakum trials. The data from the tests was as follows:

Sesame injury (%) a Yield (kg/ha) Rate 2004 2005 2004 2005 Treatment b kg/ha Lub Yoa Lub Yoa Lub Lub Yoa Check 0 0 0 0 125 1,008 314 Acifluorfen 0.56 82 38 33 18 8 641 657 LSD (0.10) 11 36 20 105 226 a Injury index: 0 = no sesame injury; 100 = complete plant death. Ratings taken 6-8 wks after herbicide application b All herbicides included a non-ionic surfactant added at 0.25% v/v or a crop oil concentrate added at 1 qt/ac.

Their conclusions were as follows: · In Lubbock where there were no weeds, acifluorfen reduced the yields, while in Yoakum, the treatment by controlling the weeds had a higher yield than the control. · In Lubbock in 2004 with there was severe injury to the sesame with intermediate injury in the other trials. POST DIR summary: No known research. Informal tests show that the acifluorfen does not damage the sesame. In the US, the first author has made the following observations: · In the Lubbock nursery in 2005, the farmer was using acifluorfen on cotton and POST DIR sprayed a sesame strip (the juvenile stage while 20" tall) filled with morningglory with the chemicals hitting the stems of the sesame about 3" from the ground. There was no visible damage to the sesame. Most of the existing morningglory plants were killed, but there was another flush with the next rain. · In Batesville, a planting seed farmer did not get metolachlor sprayed PRE over an 8 row strip in the field and there were considerable weeds in that area. A POST DIR spray of acifluorfen at 4" did not damage the majority of the sesame, but did kill minor plants where the percentage of the stem sprayed was higher because the plants were shorter. The weeds were as high as the sesame, and the herbicide did not kill all of the weeds but set back most of them so that few weeds were not visible above the sesame at the end of the season. There was a mark that resembled a bruise on the sesame stems where the spray hit.

ALACHLOR (Lasso, Alanox, Alar, Intrro, Lazo)

Sesame use: Used in commercial fields as PRE by itself or in combination with other chemicals. Most widely used herbicide for sesame. No US label. PRE summary: Selective to sesame and provides good weed control. In Bulgaria, Lyubenov and Kostadinov (1970) conducted trials in 1969 with sesame sown on chernozem smolnitsa soil on 29 May. PRE application of 4 kg/ha Lasso (alachlor) or mixtures of 4 kg/ha Patoran (metobromuron [OP]) and 3 kg/ha Afalon (linuron) with 3 kg/ha Lasso gave effective control of weeds and increased seed yields and seed oil content. In the US in California, St Andre (1970a) conducted PPI trials under furrow irrigation, planted 14 May. Variety was 215 (semi-shattering). Evaluated 2 Jun.

Stand counta Visual ratingb

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Herbicide

Weed Rate Sesame Pigweed Mustard Grass control lb/ac Lasso (alachlor) 2.0 85.6 0 0 0.6 10 4.0 54.0 0 0.6 0 10 Untreated --96.0 6.6 1.3 58.3 0 a Stand count values represent the average number of plants in 8 feet of row b Ratings based on 0-10 scale. 0 = no control or injury. 10 = perfect control or very severe injury. Injury rating reflects retardation and vigor in the growth of sesame.

Sesame injury 3.3 3.3 0

Alachlor had excellent weed control and some injury to the sesame. At the high rate, there was some reduction in stand; however, 6.7 plants per foot is considered a good stand in sesame. In the US in California, St Andre (1970b) conducted PPI (5-6.3 cm) trials under furrow irrigation, planted 25 Jun. Stand counts were done 14 Jul and the ratings 18 Jul. The barley was harvested, disked in, listed, and preirrigated. Herbicides were applied and incorporated in the same operation with planting.

Herbicide Rate lb/ac Lasso (alachlor) 2.0 65.5 9.0 4.0 55.6 2.0 Diphenamid + 3.0 66.3 4.0 Lasso 1.5 Prefar (bensulide) + 3.0 77.0 7.0 7.6 0 Lasso 1.5 Untreated --81.0 14.0 1.6 0.6 a Stand count values represent the average number of plants in 8 feet of row b Ratings based on 0-10 scale. 0 = no control or injury. 10 = perfect control or very severe injury. Injury rating reflects retardation and vigor in the growth of sesame. Stand counta Sesame Barley Visual ratingb Barley Sesame control injury 7.3 0 8.6 0 9.0 1.0

Lasso was the best in terms of less stand reduction, sesame injury, and weed control. Although the stand was somewhat reduced, the remaining stands are considered good stands. In the US in California, Fischer (1971) summarized the work that had been done between 1967 and 1970 in the San Joaquin valley to include the results of St Andre (1969, 1970a, and 1970b). In that area the concept was to grow sesame double cropped after barley or other cereals, and thus the emphasis was on controlling volunteer grasses. He summarized the results for the years as follows:

Trade name Lasso Active ingredient Alachlor Lbs/ac evaluated 2.0/4.0 Sesame tolerance Fair Barley control Good

Their overall evaluations were as follows: Alachlor provided effective weed control and at 2 lbs/ac did not adversely affect the sesame but the stand was reduced at 4 lbs/ac. In Ethiopia, Schrodter and Rawson (1984) cited Anon (1973) that the highest yields were obtained with alachlor at 2.9 kg/ha applied PRE. In the US, in California, St Andre (1973) conducted PPI trials under furrow irrigation, planted 15 May. Variety was 247 (nonshattering). Evaluated 14 Jun. Note that the stands are much lower than the other St Andre testing. Nonshattering (indehiscent) lines have much less vigor than semi-shattering or shattering lines.

Herbicide Alachlor (PRE) Rate kg/ha 2.25 Type of plot Weedy Weed free Number of plants a 230 a c 233 a Yield kg/ha 1051 a 953 a Plant vigour rating b 4.8 a 4.8 a

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Herbicide Bentazon (POST) e

Rate kg/ha 0.96

Alachlor (PRE) 2.25 Bentazon (POST) 1.92 + Bentazon (POST)d 0.96 Weedy 7d 83 e 0.8 e Weedy control 259 a 579 c 4.9 a Weed free control 314 a 1075 a 5.0 a a 1000s/ha b Scale 0-5 with 0 = majority of plants dead, 5 = all plants healthy, uniform growth. Taken 29 days after planting. c Means not followed by a common letter differ significantly (P<0.05) d Publication table is missing something; must have had another herbicide ­ probably alachlor. e The POST application was 21 days after planting

Type of plot Weedy Weed free Weedy

Number of plants a 85 bc 66 bc 7d

Yield kg/ha 210 e 545 cd 174 e

Plant vigour rating b 1.5 d 1.5 d 0.3 e

Lasso had little stand reduction, little effect on vigor, and good weed control except on mustard. The Lasso high rate was the only herbicide that did little damage to the sesame and somewhat controlled the mustard. The Lasso was the only herbicide on the test that reduced mustard without killing the sesame. In Ethiopia, Moore (1973a) evaluated herbicides for use in sesame grown on a dark brown sandy clay loam under irrigation at Melka Werer. Alachlor (1.6 kg and 2.75 kg/ha) PRE was the safest of the herbicides tested but residual activity was poor. Prometryn applied PRE gave the best overall results. In Ethiopia, Moore (1973b, 1974) carried out a trial in the higher rainfall area at Setit Humera where irrigation was not necessary. Trifluralin at 0.75 kg and 1.4 kg/ha PPI and alachlor at 2.9 kg/ha PRE gave the highest yields of sesame. In the US in California, St Andre (1974) conducted PPI (5-6.3 cm) trials under furrow irrigation, planted 28 May. Millet was seeded in the south half of each plot. Variety was Lucidi (shattering). Evaluated 13 Jul.

Herbicide Rate lb/ac Sesame vigor b 6/28 8.2 7.0 2.7 Sesame vigor b 7/13 9.2 9.0 6.0 Percent stand a 6/28 95.0 78.7 30.0 Percent stand a 7/13 87.5 77.5 17.5 Weed control c 7/13 9.5 9.7 9.7

Lasso (alachlor)

2.0 4.0 Devrinol (napropamide) + 1.0 Lasso (alachlor) 2.0 Enide (diphenamid) + 4.0 6.2 7.5 72.5 72.5 10.0 Lasso (alachlor) 2.0 Untreated --9.0 9.2 93.7 90.0 4.2/3.7 a Stands are based on an estimated percentage. Note that the untreated stands are not 100%. b Vigor evaluation is based on a 0-10 scale with 0 = very poor vigor and 10 = vigorous growing plants. c Ratings based on 0-10 scale. 0 = no control. 10 = perfect control.

Alachlor by itself at the low rate was good for vigor, stands, and weed control, but at the higher rate there was lower vigor and stand reduction. In combination with napropamide, the stands and vigor were reduced substantially although neither by itself at this rate and in 1973 testing affected the sesame as much. Similar results occurred with the diphenamid + alachlor combination. In India, Subramanian and Sankaran (1977) carried out field experiments in 1975 in summer and during kharif to study the efficiency of alachlor. In summer 1975, alachlor at 1.5 kg/ha gave a

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significantly higher yield (613 kg/ha) than the rest of the treatments. During kharif alachlor at 1.75 kg/ha was again significantly better (473 kg/ha) than other treatments. Alachlor at 1.75 kg/ha in combination with 30kg N /ha gave the maximum net income and also the highest return per rupee invested on weed control. In India, Subramanian and Sankaran (1981) conducted field experiments for 2 seasons at Coimbatore to study the effect of PRE herbicides in controlling Trianthema portulacastrum and Cyperus rotundus in sesame. Sesame was given alachlor at 1.5-1.75 kg/ha PRE in the monsoon season. Alachlor at 1.75 kg/ha effectively controlled T. portulacastrum and C. rotundus in both the seasons. Dry matter production and NPK removal by the weeds were lower with alachlor than with other treatments and were similar to those with hand weeding. In India, Schrodter and Rawson (1984) cited Guar and Tomar (1978) who found that alachlor at 2.2 kg/ha applied to previously hand weeded plots gave one of the highest yields. In the US in California, St Andre (1978) conducted PPI and PRE trials (5-6.3 cm) under furrow irrigation, planted 22 May. Weeds present were barley, ground cherry, sowthistle, pigweed, and lambsquarter. Variety was Lucidi.

Herbicide Lasso (alachlor) Lasso (alachlor) + Enide 90W (diphenamid) Lasso (alachlor) + Devrinol (napropamide) Lasso (alachlor) + Furloe 124 (chlorpropham) Untreated

a

Rate lb/ac 2.0 2.0 4.0 2.0 0.5 2.0 2.0 ---

Vigor 9.7 9.5 10 7.7

a

Grasses 6/13 6.2 8 7.5 9.7

Weed control b Grasses Broadleaf 6/22 6/13 4.5 10.0 7.0 10 5.75 9.5 10 10

Broadleaf 6/22 7.0 8.5 8.0 9.0

9.7

0

.75

5.5

5.75

Vigor scale ­ 0-10 with 0 = no vigor, 10 = excellent vigor b Weed control scale 0-10 with 0 = no control, 10 = perfect control The best combination in terms of weed control was with chlorpropham, but there was some reduction in sesame vigor. In all other treatments, the alachlor by itself or in combination did not control the grasses. All treatments had good broadleaf control initially, but over a month, some of the broadleaves were coming back. In the US in Arizona, Howell et al. (1984) had the following results:

Treat PPI PRE PRE PRE PPI PPI PRE PPI Herbicide Lasso (alachlor) Lasso (alachlor) Dymid (diphenamid a) + Lasso (alachlor) Dymid (diphenamid a) + Lasso(alachlor) Prefar (bensulide) + Lasso (alachlor) Rate /ac 3l 3l 4.8 kg 3l 4.8 kg 3l 5l 3l Mid stunt OK/no OK/no OK/no no/no OK/OK Mid stand OK/OK OK/OK OK/OK OK/OK OK/OK Broadleaf control OK/OK OK/OK OK/OK OK/OK OK/OK Grass control OK/OK OK/OK OK/OK OK/OK OK/OK Early vigor OK/OK OK/OK OK/OK OK/OK OK/OK

They concluded that alachlor provided good weed control, good early vigor, and good on stand reduction. There were some stunting issues in one trial, but the stunt ratings were close to acceptable. The bensulide/alachlor combination was only one of three trials that were OK across the board.

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In Australia in Queensland, Schrodter and Rawson (1984) evaluated PRE and POST OTT herbicides on sesame grown under weed free and weedy conditions in 3 experiments over two years. The following were the results of the first two experiments:

Herbicide Alachlor (PRE) Rate kg/ha 2.25 4.5 Number of plants a 38 ad 56 ab 59 a 52 ac Yield kg/ha 133 bd 295 ab 431 a 55d Number of plants 289 ab 307 ab 251 b 322 a Yield kg/ha 403 b 460 a 385 b 431 ab Plant height cm d 19 ab 17 bc 18 abc 20 a

Weed free control Weedy control a 1000s/ha b Means not followed by a common letter differ significantly (P<0.05) c Experiment says PRE but probably PPI d Measured 29 days after planting

The results of experiment 1 were as follows: · Alachlor had no significant effect on the populations · Yield in the weedy control was reduced 87% when compared to the weed free control. The weed free control significantly outyielded all the treatments except for the high rate of alachlor. The results of experiment 2 were as follows: · Alachlor had no effect on the crop. · The reduction of population in the weed free control was probably a loss during the hand weeding operation. In experiment 3, the successful treatments were repeated and a few new herbicides were tried as follows:

Herbicide Alachlor Rate kg/ha 2.25 Type of plot Weedy Weed free Number of plants a 230 a c 233 a 314 a 259 a Yield kg/ha 1051 a 953 a 1075 a 579 c Plant vigour rating b 4.8 a 4.8 a 5.0 a 4.9 a

Weed free control Weedy control a 1000s/ha b Scale 0-5 with 0 = majority of plants dead, 5 = all plants healthy, uniform growth. Taken 29 days after planting. c Means not followed by a common letter differ significantly (P<0.05) d Table is missing something, must have had another herbicide. e The POST application was 21 days after planting

The results of experiment 3 were as follows: · Weed competition in the weedy control reduced the yield by 46% when compared with the weed free control. · Alachlor was the safest herbicide with yield, population, and vigor similar to the weed free control. The overall conclusion was that alachlor at 2.25 kg/ha applied PRE was the most acceptable herbicide treatment. In Israel, Graph et al. (1985) showed PRE treatment with 1.0-2.0 kg/ha of alachlor was selective to sesame but caused damage when applied with a PPI trifluralin treatment. In Korea, Kim et al. (1986) conducted field trials in the sesame-producing uplands of Korea, to study the herbicide efficacy and phytotoxicity in crops grown under polyethylene film. A rate of 1.5 l/ha of alachlor gave sesame yields equivalent to that obtained with manual weed control. In Korea, a research summary (Lee 1986) recommends Alar (alachlor).

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In Venezuela, Pineda and Avila (1988) tried alachlor as a PRE, and it was comparable to the check. In Egypt in Shandaweel, Ibrahim et al. (1988) studied the effect of 5 herbicides applied singly or in tank mixtures or hoeing on sesame crops infested with various weeds in 2 field trials in 198485. Treatments included 2.30 kg/ha alachlor, 2.04kg/ha pendimethalin, 1.2 kg/ha linuron, 0.96 kg/ha diuron, and 1.92 kg/ha prometryn applied PRE individually, or as tank mixtures of alachlor with the other herbicides. In India, Bansode and Shelke (1991) assessed six weed control treatments (an unweeded control, hand weeding (HW) + hoeing 3 weeks after sowing (WAS), and PRE alachlor at 0.75 or 1.5 l/ha in field trials during the kharif of 1988 with sesame (cv. Punjab-1 and T-85). PRE alachlor applied to cv. Punjab-1 combined with HW + hoeing gave highest yields (689 kg) compared to HW + hoeing alone (583 kg) and all other treatments. In Thailand, a field guide (Anon 1997) states that hand weeding is practiced twice at 15 and 25 days after emergence. The PRE herbicides alachlor (1.2-1.5 l/ha) is also recommended in case of labor shortage. In Brazil in Paraiba, Viera et al. (1998) tested the efficacy of mixtures of diuron (0.75, 1.0 and 1.25 kg/ha) and alachlor (1.44 kg/ha) as PRE herbicides. After 15 days, significantly greater phytotoxicity was observed following treatment with the highest dose of diuron plus alachlor (21.25%). Control ranged from 97 to 99% after 30 days and from 96 to 98% after 60 days. There were no significant differences for the height of the 1st fruiting branch, the number of fruits per plant, and the yield between the different treatments and mowing. In Venezuela, Mazzani (1999) cited the following data from Caraballo et al. (1986). In experimental plots the best results were from using Lazo (3-4 liters/ha) as a PRE and Karmex (2 liters/ha) as a postemergent. Lazo dose, l / ha Plant height, cm Yield, kg / ha 6 174 1,008 5 170 833 4 172 848 3 170 810 Cleaned by hand 166 1,042 No cleaning 154 536

Mazzani (1999) cites Villaroel et al. (1988) also showed the most efficient control with Lazo (alachlor) at a dose of 3.5 liters/ha.

In India in Uttar Pradesh, Om et al. (2001) investigated the effects of N fertilizer application and weed control measures on sesame during 1995 and 1996. Treatments consisted of N levels, i.e. 0, 30, 60 and 90 kg/ha, and weed control treatments, i.e. weedy control, hand weeding 3 weeks after sowing, PRE application of alachlor at 1.0 kg/ha and PRE application of alachlor (1.0 kg/ha) + hand weeding. N fertilizer rate did not significantly affect the weed population. Alachlor was not as effective as fluchloralin [OP]. In Honduras, a grower guide (Anon 2002) states that the use of PRE herbicides such as alachlor (Lasso) has proved to be very efficient in the control of weeds in sesame.

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In India in Rajasthan, Dungarwal et al. (2003) conducted a field experiment during the kharif seasons of 1997 and 1998 to evaluate the relative efficacy of alachlor applied alone or in combination with one hoeing at four weeks after sowing ( WAS) to control weeds in sesame (cv. TC 25). On average, season-long weed competition caused 50% reduction in seed yield. Among the herbicides, the PRE application of alachlor at 2.0 kg/ha combined with one hoeing at 4 WAS registered the highest weed control efficiency which enhanced yield attributes leading to higher seed yield (530 kg/ ha) and net return (Rs. 4275/ha). In Pakistan, a grower guide (Panhwar 2005) recommends alachlor 1.75 kg/ha. In India in Rajasthan, Chandawat et al. (2004) conducted a field experiment to look at the efficacy of hand weeding 20 and/or 30 days after sowing (DAS), 1.5 kg/ha of alachlor PRE alone or in combination with hand weeding 30 DAS, PPI of 2.0 kg/ha alachlor alone or in combination with hand weeding 30 DAS. Weed control efficiency was highest (88%) with the PRE 1.5 kg/ha alachlor and 0.5 kg/ha pendimethalin in combination with hand weeding 30 DAS. Plant height was highest with the application of alachlor in combination with hand weeding. Application of 2 kg/ha alachlor in combination with hand weeding resulted in the highest number of primary branches per plant (45), pooled seed yield (713 kg/ha), net returns (10736 kg/ha), and benefit cost ratio (2.17). In India in Himachal Pradesh, Anil and Thakur (2005) studied the effects of sowing method (line sowing or broadcasting) and weed control methods (hand weeding at 20 and 40 days after sowing or DAS, and 1.5 kg/ha alachlor with or without hand weeding once) on the productivity of sesame (cv. Brajeshwari) monocropping or sesame + black gram (UG 218) were studied during the kharif of 2003 and 2004. Alachlor + hand weeding recorded the lowest weed density (21.4/m2) and dry matter (8.5 g/m2). Hand weeding twice reduced the weed density and dry matter accumulation by 57.5 and 60.4%, respectively, over the control. The highest sesame seed yields were obtained with 1.5 kg alachlor/ha singly (260 kg/ha) or in combination with hand weeding (284 kg/ha). In India in Tamil Nadu, Gnanavel and Anbhazhagan (2006) conducted a field experiment in summer 2002 to evaluate the efficacy of different PRE herbicides and herbicide along with hand weeding (HW) in controlling weeds in irrigated sesame cv. TMV 5. The treatments included 2.0 kg/ha alachlor and 1.0 kg/ha alachlor + HW at 30 DAS. The application of 0.15 kg/ha oxyfluorfen with one HW at 30 DAS was significantly better in terms of weed control index (92.7%) and seed yield (0.92 t/ha). In Mexico, a grower guide for Michoacan (Anon, 2007a) recommends the use alachlor by itself by the names Lasso (2.5 lt/ha) and Alanox (3.0 lt/ha) as a PRE. It is also used in combination with linuron and diuron. With linuron used by the names Lasso afalon (1.0 lt + 0.5 kg) or Alanox + Linorox ( 1.5 lt +0.5 kg/ha). With diuron it used as Lasso + Karmex, Alanox + Diurol, or Herbilaz crisuron (2.0 lt + 0.5 kg/ha). In all cases it is mixed with 250-300 liters of water. In El Salvador, a growers guide (Anon 2007c) recommends 2.8 l/ha of Lasso (alachlor). In Thailand, W. Wongyai (2007, pers. commun.) successfully applied alachlor in her nurseries in the wet growing season in February 2007. In the US in South Carolina, Brad Sadler (2007, pers.commun.) has grown sesame for bird hunting for the past 20 years. He has used both Lasso (alachlor) and Dual (metolachlor) in alternating years in order to control yellow and purple nut sedge. He waits for a good probability

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of rain and then sprays the material and incorporates it before planting. He has had good stands with both materials. He has not noted any difference on the sesame with either product. POST OTT summary: No known research, but farmers have applied it without an apparent effect on the sesame to provide residual weed control. In the US in South Carolina, Brad Sadler (2007, pers.commun.) has grown sesame for bird hunting for the past 20 years. In a few years he has sprayed Lasso (alachlor) over the top of the seedlings and found no damage with the alachlor. POST DIR summary: No known research. System summary: Bentazon is not a good POST herbicide in combination with alachlor. In Australia in Queensland, Schrodter and Rawson (1984) evaluated PRE and POST OTT herbicides on sesame grown under weed free and weedy.

Herbicide Alachlor Rate kg/ha 2.25 Type of plot Weedy Weed free Weedy Number of plants a 230 a c 233 a 7d Yield kg/ha 1051 a 953 a 174 e Plant vigour rating b 4.8 a 4.8 a 0.3 e

Alachlor (PRE) 2.25 Bentazon (POST) 1.92 Weed free control 314 a 1075 a 5.0 a Weedy control 259 a 579 c 4.9 a a 1000s/ha b Scale 0-5 with 0 = majority of plants dead, 5 = all plants healthy, uniform growth. Taken 29 days after planting. c Means not followed by a common letter differ significantly (P<0.05) d Table is missing something, must have had another herbicide. e The POST application was 21 days after planting

All of the PRE herbicides tested with bentazon ended up with toxic results. As can be seen by itself, alachlor had good results. Alochlor characteristics: (Anon 1994, 1998) · Other crop uses: Has been used as PREPLANT, PRE, and PPI. It controls yellow nutsedge, many annual grasses such as barnyardgrass, crabgrass, foxtail, panicum, goosegrass, and certain broadleaf weeds such as galinsoga, lambsquarters, purselane, and black nightshade. · Description: Cream to wine-red colored solid, odorless. · Symptomology: Most susceptible grass and broadleaf weeds fail to emerge. Susceptible monocots that do emerge appear twisted and malformed. Broadleaf seedlings may have slightly cupped or crinkled leaves. · Absorption/translocation: Absorbed primarily by emerging plant shoots (grass coleoptile, broadleaf hypocotyl or epicotyl), secondarily by seedling roots. Plants beyond seedling stage readily absorb alachlor into roots and translocate it acropetally throughout the shoots with primary accumulation in vegetative parts. Translocation in established plants is irrelevant to mechanism of action because alachlor is phytotoxic only to emerging seedlings. · Mechanism of action: Site of action is not known, but it is known to inhibit biosynthesis of fatty acids, lipids, proteins, and flavonoids. Alachlor affects susceptible weeds before emergence, but does not inhibit seed germination. · Sorption: · Transformation:

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· · · ·

- Photodegradation: Half-life is 80 days on soil and >239 days in water. Minor contribution to losses in field. - Other degradation: Is negligible in sterile soil. Half-life in aerobic soil is 6.1-15.8 days but 4.5 days in anaerobic conditions. Persistence: Average field half-life is 21 days. It generally provides 6-10 weeks of weed control, but varies with soil type and weather conditions. Alachlor residues do not persist long enough to injure crops the following season. Mobility: Low to moderate mobility in soil. Volatilization: Low losses. Miscellaneous information:

Common name Trade name Date Avg rate (lbs/ac) LD50 rat (mg/kg) Alachlor Lasso 1969 4.75 1,000 Current sample of label: http://www.monsanto.com/monsanto/ag_products/pdf/labels_msds/intrro_label.pdf

Using the sample label above for Intrro which is used on sorghum, soybeans, and peanuts, there are rotational restrictions depending on other herbicides used in the tank mixes. It is best to consult the current label for current restrictions.

ALLIDOCHLOR - CDAA (Randox)

PRE summary: At low rates was non-toxic; at higher rates caused chlorosis and stand reductions. In the US in Mississippi, Culp and McWhorter (1965) cited Culp and McWhorter (1959) that allidochlor at 6 lb/ac caused chlorosis and stand reductions. Allidochlor at 3 lb/ac was non-toxic. POST summary: No known research.

AMETRYN (Gesapax)

PRE summary: Toxic to sesame with close to no germination. In Argentina in Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3 replications. There were 3 rains before emergence. The PRE test populations and weed control are as follows:

Weed control a 19 DDA b Herbicide Gesapax

a a

30 DDA

Active ingredient Rate/ha Stand Ama Rha Ama Rha Ametryn 3 kg 0 100 55 100 45 Clean check 4.1 100 100 100 100 Weedy check 3.2 0 0 0 0 a Weed control with 0 = no control and 100 = complete control. Ama = Amaranthus quitensis and Rha = Raphanus sativus b DDA = days after application

There were four ratings done 19, 30, 60, and 88 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is

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the hundred seed weight of capsules in the center of the capsule zone. The number of seeds were counted and the seed weight per capsule (SWC) and was taken. The PRE data was as follows:

19 DDA Ametryn 0 Clean check 83 Weedy check 77 a DDA = days after application Active ingredient 30 DDA 0 87 77 60 DDA 0 88 78 88 DDA 2 82 72 Yield (g/m) 59.9 de 53.8 bcde W100 (g) 0.284 0.297 Sd/cap 71 69 SWC (g) 0.202 0.205

Ametryn is toxic to sesame preventing total germination. POST summary: No known research.

AMIPROPHOSMETHYL (Bay-NTN 6867)

PRE summary: Toxic to sesame by substantially reducing vigor and stands. In the US in California, St Andre (1974) conducted PPI (5-6.3 cm) trials under furrow irrigation, planted 28 May. Millet was seeded in the south half of each plot. Variety was Lucidi (shattering). Evaluated 13 Jul.

Percent Weed Sesame Sesame Percent control c vigor b vigor b stand a stand a 6/28 7/13 7/13 6/28 7/13 Bay-NTN 6867 1.5 5.0 7.7 56.2 62.5 9.2 (amiprophosmethyl) 3.0 4.0 6.2 15.7 16.2 9.2 Untreated --9.0 9.2 93.7 90.0 4.2/3.7 a Stands are based on an estimated percentage. Note that the untreated stands are not 100%. b Vigor evaluation is based on a 0-10 scale with 0 = very poor vigor and 10 = vigorous growing plants. c Ratings based on 0-10 scale. 0 = no control. 10 = perfect control. Herbicide Rate lb/ac

Amiprophosmethyl reduced the sesame vigor and stands substantially, but did have good weed control. POST summary: No known research.

ASULAM (MB-9057)

PRE summary: Somewhat selective to sesame, but poor weed control. In the US in California, Fischer (1971) summarized the work that had been done between 1967 and 1970 in the San Joaquin valley to include the results of St Andre (1969, 1970a, and 1970b). In that area the concept was to grow sesame double cropped after barley or other cereals, and thus the emphasis was on controlling volunteer grasses. He summarized the results for the years as follows:

Trade name MB-9057 Active ingredient Asulam Lbs/ac evaluated 3.0 Sesame tolerance Good Barley control Poor

POST summary: No known research.

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ATRAZINE (Aatrex, Gesaprim)

PRE summary: Residues from previous crops can be toxic to sesame. In Somalia, Warfa and Noor (1978) conducted pot trials in 1976 in soil without or containing Gesaprim (atrazine) residues. Sesame was sown in the pots to assess the sensitivity to the residue. In soil treated 6 months earlier with Gesaprim there was no growth by sesame. In soil treated 8 months earlier with Gesaprim there was no significant difference in seedling dry matter between treated and untreated soils. In Australia, a grower guide for South Burnett (Sapin et al. 2000) stated, "Sesame will not tolerate atrazine." In the US, the first author has made the following observations: · Tens of thousands of acres of sesame have been planted after corn and sorghum the summer before, and there is only one known problem. In one year, there was very little rain between the fall application of atrazine and the planting of the sesame in the spring. The sesame stand was lost, and extension personnel felt that the plants had herbicide damage. · There has been no attempt to plant sesame after hailed out corn or sorghum for fear of atrazine damage. POST OTT summary: Toxic to sesame. Reduces the production substantially, but does not kill the sesame. In the US in South Texas, Grichar and Langham (2003) conducted a POST OTT test. A 5 ft swath of herbicides was sprayed across three rows of five lines leaving 15 ft of each row untouched to allow a direct within row comparison of the effects of the treatments. The herbicides were sprayed over the top in the juvenile stage when the plants were about 18" tall. There was a dual purpose: (1) find herbicides that were selective to sesame and (2) find herbicides that would control volunteer sesame in other crops. In this test, there were no weeds since the main thrust of the study was to look at the effects of the herbicide on the sesame. There were no replications in that the idea was to take the better lines and test them in Grichar et al. (2007). At the end of the ripening phase, the plots were evaluated in terms of percentage production compared to the untouched plants in the same row.

Treatment Atrazine Rate 0.5x 1.0x Average S26 60 40 37 S27 60 50 49 S28 60 40 37 S29 60 60 48 132 50 40 31 Average 58 46 40

Atrazine reduced the production substantially even though it was better than most other treatments. POST DIR summary: No known research.

BENEFIN (Balan)

PRE summary: Toxic to sesame. In the US in California, Fischer (1971) summarized the work that had been done between 1967 and 1970 in the San Joaquin valley to include the results of St Andre (1969, 1970a, and 1970b).

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In that area the concept was to grow sesame double cropped after barley or other cereals, and thus the emphasis was on controlling volunteer grasses. He summarized the results for the years as follows:

Trade name Balan Active ingredient Benefin Lbs/ac evaluated 1.25 Sesame tolerance Poor Barley control Erratic

Benefin is toxic to sesame and provided erratic control of barley. POST summary: No known research.

BENFURESATE (Cyperal)

PRE summary: Higher rates toxic to sesame. In Nicaragua, Soto and Silva (1987) conducted plot trials at 2 sites in Nicaragua. C.v. China Roja sown in August was treated immediately with 1.4 or 2.9 l/ha Cyperal (benfuresate). Assessment of weed and crop populations 15, 30, and 45 days after treatment showed that higher rates of Cyperal were phototoxic. POST summary: No known research.

BENSULIDE (Prefar)

PRE summary: Selective to sesame but erratic grass and broadleaf control. In the US in California, St Andre (1969) conducted PPI trials under furrow irrigation, planted 10 Jun. Variety was Baco planted at 2.5 lbs/ac. The stand counts were done 5 Jun and the ratings 10 Jun.

Visual rating b Herbicide Rate Barley Sesame lb/ac control injury Prefar (bensulide) 5.0 51.6 11.3 4.6 0 Untreated --55.3 21.6 0 0 a Stand count values represent the average number of plants in 8 feet of row b Ratings based on 0-10 scale. 0 = no control or injury. 10 = perfect control or very severe injury. Injury rating reflects retardation and vigor in the growth of sesame. Stand count a Sesame Barley

Prefar had no injury to the sesame, but had only moderate control of the barley. In the US in California, St Andre (1970a) conducted PPI trials under furrow irrigation, planted 14 May. Variety was 215 (semi-shattering). Evaluated 2 Jun.

Herbicide Rate Sesame Grass lb/ac Prefar (bensulide) 5.0 65.0 0 1.3 1.3 Untreated --96.0 6.6 1.3 58.3 a Stand count values represent the average number of plants in 8 feet of row b Ratings based on 0-10 scale. 0 = no control or injury. 10 = perfect control or very severe injury. Injury rating reflects retardation and vigor in the growth of sesame. Stand count a Pigweed Mustard Visual rating b Weed Sesame control injury 8.6 2.3 0 0

Prefar had good weed control and minimum injury to the sesame.

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In the US in California, St Andre (1970b) conducted PPI (5-6.3 cm) trials under furrow irrigation, planted 25 Jun. Stand counts were done 14 Jul and the ratings 18 Jul. The barley was harvested, disked in, listed, and preirrigated. Herbicides were applied and incorporated in the same operation with planting.

Herbicide Rate lb/ac Prefar (bensulide) 6.0 83.0 3.6 Prefar + 3.0 77.0 7.0 Lasso (alachlor) 1.5 Untreated --81.0 14.0 1.6 0.6 a Stand count values represent the average number of plants in 8 feet of row b Ratings based on 0-10 scale. 0 = no control or injury. 10 = perfect control or very severe injury. Injury rating reflects retardation and vigor in the growth of sesame. Stand counta Sesame Barley Visual ratingb Barley Sesame control injury 8.6 0 7.6 0

Prefar had no sesame injury, did not affect the stand much, and had good weed control. In the US in California, Fischer (1971) summarized the work that had been done between 1967 and 1970 in the San Joaquin valley to include the results of St Andre (1969, 1970a, and 1970b). In that area the concept was to grow sesame double cropped after barley or other cereals, and thus the emphasis was on controlling volunteer grasses. He summarized the results for the years as follows:

Trade name Prefar Active ingredient Bensulide Lbs/ac evaluated 4.0/6.0 Sesame tolerance Good Barley control Poor

Their overall evaluations were as follows: Bensulide was well tolerated by sesame but failed to adequately control volunteer barley and was also erratic in controlling broadleaf weeds. In the US, in California, St Andre (1973) conducted PPI trials under furrow irrigation, planted 15 May. Variety was 247 (nonshattering). Evaluated 14 Jun. Note that the stands are much lower than the other St Andre testing. Nonshattering (indehiscent) lines have much less vigor than semi-shattering or shattering lines.

Herbicide Rate Sesame Sesame Pigweed lb/ac vigorb Prefar (bensulide) 5.0 10 14.7 1 Prefar + 4.0> 9.0 12.0 0 Lasso (alachlor) 2.0> Untreated --10 12.2 7.5 5.5 23 a Stand count values represent the average number of plants in 8 feet of row in 4 replications except for the pigweed which was only present in the 3rd replication. b Vigor evaluation is based on a 0-10 scale with 0 = very poor vigor and 10 = vigorous growing plants. Stand count a Mustard Japanese millet 7.5 0 7.5 2.0

Bensulide had little stand reduction, little effect on vigor, and good weed control except on mustard. In the US in California, St Andre (1974) conducted PPI (5-6.3 cm) trials under furrow irrigation, planted 28 May. Millet was seeded in the south half of each plot. Variety was Lucidi (shattering). Evaluated 13 Jul.

Herbicide Rate lb/ac 5.0 --Sesame vigor b 6/28 8.7 9.0 Sesame vigor b 7/13 9.5 9.2 Percent stand a 6/28 95.0 93.7 Percent stand a 7/13 91.2 90.0 Weed control c 7/13 10.0 4.2/3.7

Prefar (bensulide) Untreated

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a

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Stands are based on an estimated percentage. Note that the untreated stands are not 100%. Vigor evaluation is based on a 0-10 scale with 0 = very poor vigor and 10 = vigorous growing plants. c Ratings based on 0-10 scale. 0 = no control. 10 = perfect control.

b

Bensulide had no effect on sesame stands or vigor and had excellent weed control. In the US in California, St Andre (1978) conducted PPI trials (5-6.3 cm) under furrow irrigation, planted 22 May. Weeds present were barley, ground cherry, sowthistle, pigweed, and lambsquarter. Variety was Lucidi.

Herbicide Rate lb/ac 6.0 4.0 4.0 4.0 2.0 Vigor

a

Prefar (bensulide) 9.5 Prefar (bensulide) + 9.7 Enide 90W (diphenamid) Prefar (bensulide) + 8.5 10 9.75 Furloe 124 (chlorpropham) Prefar (bensulide) + 4.0 9.0 1.5 2.0 Dual (metolachlor) 2.0 Untreated --9.7 0 .75 a Vigor scale ­ 0-10 with 0 = no vigor, 10 = excellent vigor b Weed control scale 0-10 with 0 = no control, 10 = perfect control

Grasses 6/13 3.7 6.2

Weed control b Grasses Broadleaf 6/22 6/13 3.25 9.0 7.0 9.5 10

Broadleaf 6/22 8.0 7.5 8.0

9.7 5.5

8.5 5.75

Bensulide had little effect on the sesame vigor and had good control over the broadleaves, but by itself had little control on grasses. The best combination was with chlorpropham. In the US in Arizona, Howell et al. (1984) had the following results:

Treat PPI PPI PPI PRE PPI Herbicide Prefar (bensulide) Prefar (bensulide) + Dual (metolachlor) Prefar (bensulide) + Lasso (alachlor) Rate /ac 5l 5l 3l 5l 3l Mid stunt OK/OK no/no OK/OK Mid stand OK/OK OK/OK OK/OK Broad cont no OK/OK OK/OK Grass cont OK/OK OK/OK OK/OK Early vigor OK/OK no/no OK/OK

They concluded that bensulide was good except on broadleaf control as would be expected. The PRE bensulide/PPI alachlor was only one of three treatments that were OK across the board. POST summary: No known research.

BENTAZON (Adagio, Basagran, Bendioxide, Entry, Leader, Pledge)

PRE summary: No known research. POST OTT summary: Toxic to sesame. There is a substantial reduction in yield, population, and vigor, but did not kill the sesame. In Australia in Queensland, Schrodter and Rawson (1984) evaluated PRE and POST OTT herbicides on sesame grown under weed free and weedy conditions in Lockyer Valley in 4 experiments over two years. The variety Palmetto was used. The first two experiments were with PRE herbicides and the last two included POST herbicides. The POST applications were done 21 days after planting while the plants were in the third true leaf stage. In the first POST

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experiment, the successful PRE treatments were repeated along with a POST treatment of bentazon.

Herbicide Alachlor (PRE) Linuron (PRE) Bentazon (POST) e Rate kg/ha 2.25 2.25 0.96 Type of plot Weedy Weed free Weedy Weed free Weedy Weed free Weedy Number of plants a 230 a c 233 a 65 bc 122 b 85 bc 66 bc 7d Yield kg/ha 1051 a 953 a 634 bc 875 ab 210 e 545 cd 174 e Plant vigour rating b 4.8 a 4.8 a 2.8 c 3.5 b 1.5 d 1.5 d 0.3 e

Alachlor (PRE) 2.25 Bentazon (POST) 1.92 Linuron (PRE) 2.25 Weedy 49 c 327 de 1.5 d Bentazon (POST) 0.96 + Bentazon (POST)d 0.96 Weedy 7d 83 e 0.8 e Weedy control 259 a 579 c 4.9 a Weed free control 314 a 1075 a 5.0 a a 1000s/ha b Scale 0-5 with 0 = majority of plants dead, 5 = all plants healthy, uniform growth. Taken 29 days after planting. c Means not followed by a common letter differ significantly (P<0.05) d Publication table is missing something; must have had another herbicide ­ probably alachlor. e The POST application was 21 days after planting

The results of the experiment were as follows: · Weed competition in the weedy control reduced the yield by 46% when compared with the weed free control. · Bentazon reduced yield, population, and vigor. In the US in South Texas, Grichar et al. (2001b) conducted POST OTT studies in weed free areas at Yoakum and Uvalde from 1994 to 1997. The varieties used were Sesaco 11, 17, or 18. The herbicides were applied over the top 3-4 wk after planting in Yoakum and 6 wk after planting in Uvalde. Sesame was 30-48 cm in height at the time of application. Planting dates in Yoakum were 26 May 1994, 11 July 1995, 12 July 1996, and 1 July 1997. Planting date in Uvalde was 28 April 1995. Ratings of stunting (0= no stunting and 100 = total stunting) were done 3 weeks after herbicide application as shown below.

Rate (kg/ha) Check Bentazon LSD (0.05) Rate (kg/ha) Check Bentazon LSD (0.05) Rate (kg/ha) Check Bentazon 0.56 0.56 1.12 0.56 1.12 94 YOA 0 38 65 28 94 YOA 91 76 45 26 94 YOA 408 286 95 UVA 0 55 33 19 95 YOA 110 110 103 32 95 UVA 844 692 95 YOA 0 9 14 12 96 YOA 71 58 45 23 95 YOA 482 432 96 YOA 0 7 23 22 97 YOA 74 67 63 16 96 YOA 419 237 97 YOA 501 528 Avg 531 435 % check 82 97 YOA 0 5 20 12

There was stunting but not severe. The effects on plant height (cm) were as follows:

There was some reduction in plant height. The yields (kg/ha) were as follows:

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Bentazon LSD (0.05)

Rate (kg/ha) 1.12

94 YOA 86 248

95 UVA 786 210

95 YOA 460 255

96 YOA 195 217

97 YOA 549 NS

Avg 415

% check 78

Bentazon reduced the yields by about 20%, but it is one of the few treatments that did not do major damage to the sesame. In Argentina in Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3 replications. There were 3 rains before emergence. The POST OTT herbicides were applied 19 days after planting. The weed control data was taken 13 days after application and was as follows:

Herbicide Basagran Active ingredient Rate/ha Ama a Bentazon 1400 cc 40 Weed-free check 100 Weedy check 0 Weed control with 0 = no control and 100 = complete control. Rha = Raphanus sativus Rha a 100 100 0 Ama = Amaranthus quitensis and

a

There were three ratings done 13, 43, and 70 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight from capsules in the center of the capsule zone. The number of seeds were counted and the seed weight per capsule (SWC) and was taken. The POST OTT data was as follows:

13 43 DDAa DDA Bentazon 20 18 Weed-free check 81 83 Weedy check 75 71 a DDA = days after application Active ingredient 70 DDA 18 78 65 Yieldg (g/m) 48.4 ab 50.7 ab W100 (g) 0.300 0.300 Sd/cap SWC (g) 0.222 0.188

74.1 62.8

The bentazon severely damaged the sesame and little stand remained. POST DIR summary: No known research. System summary: In Australia in Queensland, Schrodter and Rawson (1984) evaluated PRE and POST OTT herbicides on sesame grown under weed free and weedy conditions in Lockyer Valley in 4 experiments over two years. The variety Palmetto was used. The first two experiments were with PRE herbicides and the last two included POST herbicides. The POST applications were done 21 days after planting while the plants were in the third true leaf stage. In the first POST experiment, the successful PRE treatments were repeated along with a POST treatment of bentazon.

Herbicide Bentazon (POST) e Alachlor (PRE) Alachlor (PRE) Bentazon (POST) Linuron (PRE) Rate kg/ha 0.96 2.25 2.25 1.92 2.25 Type of plot Weedy Weed free Weedy Weed free Weedy Weedy Number of plants a 85 bc c 66 bc 230 a c 233 a 7d 65 bc Yield kg/ha 210 e 545 cd 1051 a 953 a 174 e 634 bc Plant vigour rating b 1.5 d 1.5 d 4.8 a 4.8 a 0.3 e 2.8 c

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Herbicide

Rate kg/ha

Linuron (PRE) 2.25 Bentazon (POST) 0.96 + Bentazon (POST)d 0.96 Weedy 7d 83 e 0.8 e Weedy control 259 a 579 c 4.9 a Weed free control 314 a 1075 a 5.0 a a 1000s/ha b Scale 0-5 with 0 = majority of plants dead, 5 = all plants healthy, uniform growth. Taken 29 days after planting. c Means not followed by a common letter differ significantly (P<0.05) d Original table is missing something, must have had another herbicide.

Type of plot Weed free Weedy

Number of plants a 122 b 49 c

Yield kg/ha 875 ab 327 de

Plant vigour rating b 3.5 b 1.5 d

The results of the experiment were as follows: · Weed competition in the weedy control reduced the yield by 46% when compared with the weed free control. · All treatments using bentazon reduced yield, population, and vigor. It can be seen when alachlor and linuron were used by themselves, there was little damage, but when bentazon was used as a POST OTT, there was considerable damage to the sesame.

BIFENOX (Modown)

PRE summary: No known research. POST OTT summary: Toxic to sesame, almost totally wiped out the sesame. In Australia in Queensland, Schrodter and Rawson (1984) evaluated PRE and POST OTT herbicides on sesame grown under weed free and weedy conditions in Lockyer Valley in 4 experiments over two years. The variety Palmetto was used. The first two experiments were with PRE herbicides and the last two included POST herbicides. The POST applications were done 21 days after planting while the plants were in the third true leaf stage.

Herbicide Bifenox Weed free control Weedy control a 1000s/ha b Scale 0-5 with 0 = majority of plants dead, 5 = all plants healthy, uniform growth. Taken 29 days after planting. c Means not followed by a common letter differ significantly (P<0.05) Rate kg/ha 2.0 Number of plants a 3bc 312 a 290 a Yield kg/ha 57 d 937 ab 492 c Plant vigour rating b 0d 5.0 a 5.0 a

Bifenox caused serious crop damage. POST DIR summary: No known research.

BROMOXYNIL (Buctril, Weedex)

PRE summary: No known research.

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POST OTT summary: Toxic to sesame in all but one test with substantial yield reduction. In the one test where yield was higher, there was considerable weed pressure in check. In a commercial use, bromoxynil stunted the sesame and the weeds, but the weeds recovered first. In Australia in Queensland, Schrodter and Rawson (1984) evaluated PRE and POST herbicides on sesame grown under weed free and weedy conditions in Lockyer Valley in 4 experiments over two years. The variety Palmetto was used. The first two experiments were with PRE herbicides and the last two included POST herbicides. The POST applications were done 21 days after planting while the plants were in the third true leaf stage. The second POST experiment tried a few other POST herbicides with the following results

Herbicide Bromoxynil Rate kg/ha 0.28 0.42 Number of plants a 249 a c 209 a 312 a 290 a Yield kg/ha 1077 a 802 ab 937 ab 492 c Plant vigour rating b 3.7 b 2.3 c 5.0 a 5.0 a

Weed free control Weedy control a 1000s/ha b Scale 0-5 with 0 = majority of plants dead, 5 = all plants healthy, uniform growth. Taken 29 days after planting. c Means not followed by a common letter differ significantly (P<0.05)

The results of the experiment were as follows: Bromoxynil produced yields similar to the control treatments despite the observed effect on crop vigor and populations. The sesame plants showed good recovery. In the US in South Texas, Grichar et al. (2001b) conducted POST OTT studies in weed free areas at Yoakum and Uvalde from 1994 to 1997. The varieties used were Sesaco 11, 17, or 18. The herbicides were applied over the top 3-4 wk after planting in Yoakum and 6 wk after planting in Uvalde. Sesame was 30-48 cm in height at the time of application. Planting dates in Yoakum were 26 May 1994, 11 July 1995, 12 July 1996, and 1 July 1997. Planting date in Uvalde was 28 April 1995. Ratings of stunting (0= no stunting and 100 = total stunting) were done 3 weeks after herbicide application as shown below.

Rate (kg/ha) Check Bromoxynil LSD (0.05) Rate (kg/ha) Check Bromoxynil LSD (0.05) Rate (kg/ha) Check Bromoxynil LSD (0.05) 0.28 0.56 0.28 0.56 0.28 0.56 94 YOA 0 39 40 28 94 YOA 91 71 49 26 94 YOA 408 0 0 248 95 UVA 0 50 58 19 95 YOA 110 107 99 32 95 UVA 844 793 822 210 95 YOA 0 9 9 12 96 YOA 71 54 48 23 95 YOA 482 427 309 255 96 YOA 0 3 33 22 97 YOA 74 53 57 16 96 YOA 419 307 255 217 97 YOA 501 514 427 NS Avg 531 408 363 % check 77 68 97 YOA 0 28 19 12

Bromoxynil stunted the sesame. The effects on plant height (cm) were as follows:

Bromoxynil reduced the plant height substantially. The yields (kg/ha) were as follows:

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Although bromoxynil reduced the yields by 25%, it may be the choice for an over the top POST if the broadleaf weeds are so bad that the field can be lost. In the US in South Texas, Grichar and Langham (2003) conducted a POST OTT test. A 5 ft swath of herbicides was sprayed across three rows of five lines leaving 15 ft of each row untouched to allow a direct within row comparison of the effects of the treatments. The herbicides were sprayed over the top in the juvenile stage when the plants were about 18" tall. There was a dual purpose: (1) find herbicides that were selective to sesame and (2) find herbicides that would control volunteer sesame in other crops. In this test, there were no weeds since the main thrust of the study was to look at the effects of the herbicide on the sesame. There were no replications in that the idea was to take the better lines and test them in Grichar et al. (2007). At the end of the ripening phase, the plots were evaluated in terms of percentage production compared to the untouched plants in the same row.

Treatment Bromoxynil Rate 0.5x 1.0x Average S26 40 40 37 S27 50 50 49 S28 50 40 37 S29 50 40 48 132 49 30 31 Average 48 40 40

Bromoxynil was better than many of the treatments in the test, but there was severe production reduction. In the US, Grichar and Dotray (2007) conducted POST OTT studies in two locations in Texas (Yoakum and Lubbock) in 2004 and 2005. The herbicides were applied in the pre-reproductive stage when the plants were about 60 cm tall. The Lubbock trials were virtually weed free while there were weeds in the Yoakum trials. The data from the tests was as follows:

Sesame injury (%) a Yield (kg/ha) Rate 2004 2005 2004 2005 Treatment b kg/ha Lub Yoa Lub Yoa Lub Lub Yoa Check 0 0 0 0 125 1,008 314 Bromoxynil 0.56 37 40 25 10 39 883 638 LSD (0.10) 11 36 20 105 226 a Injury index: 0 = no sesame injury; 100 = complete plant death. Ratings taken 6-8 wks after herbicide application b All herbicides included a non-ionic surfactant added at 0.25% v/v or a crop oil concentrate added at 1 qt/ac.

Their conclusions were as follows: · In Lubbock where there were no weeds, the treatment reduced the yield, while in Yoakum the treatment by controlling the weeds had a higher yield than the control. · Bromoxynil showed similar results as in a previous study, where Grichar et al. (2001b) reported that bromoxynil was intermediate in sesame injury. In Argentina in Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3 replications. There were 3 rains before emergence. The POST OTT herbicides were applied 19 days after planting. The weed control data was taken 13 days after application and was as follows:

Herbicide Weedex Active ingredient Rate/ha Ama a Rha a Bromoxynil 1000 cc 40 95 Weed-free check 100 100 Weedy check 0 0 Weed control with 0 = no control and 100 = complete control. Ama = Amaranthus quitensis and Rha = Raphanus sativus

a

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There were three ratings done 13, 43, and 70 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight from capsules in the center of the capsule zone. The number of seeds were counted and the seed weight per capsule (SWC) and was taken. The POST OTT data was as follows:

13 43 DDAa DDA Bromoxynil 28 28 Weed-free check 81 83 Weedy check 75 71 a DDA = days after application Active ingredient 70 DDA 37 78 65 Yieldg (g/m) 34.6 a 48.4 ab 50.7 ab W100 (g) 0.282 0.300 0.300 Sd/cap 71.3 74.1 62.8 SWC (g) 0.201 0.222 0.188

The bromoxynil damaged the sesame and the stand, and it reduced the yield substantially. It also had very poor weed control on the Amaranthus. In Argentina, the first author had the following observations: · There was a sesame field that was clean from the metolachlor PRE, but at about 3-4 weeks there was a severe flush of nabo (Raphanus sativus). Bromoxynil was applied over the top and it did not kill the nabo or the sesame, but it set the sesame back severely to the point that the nabo grew over the sesame and reduced yields substantially. In the one area where the bromoxynil was applied earlier when the nabo was young, there was reasonable weed control and the sesame was taller. POST DIR summary: No known research.

CARBOTHIOATE (R-12001)

PRE summary: Toxic to sesame, but did not kill sesame. In the US in California, St Andre (1969) conducted PPI trials under furrow irrigation, planted 10 Jun. Variety was Baco planted at 2.5 lbs/ac. The stand counts were done 5 Jun and the ratings 10 Jun.

Visual rating b Herbicide Rate Barley Sesame lb/ac control injury R-12001 (carbuthioate) 3.0 31.0 4.3 6.6 4.0 6.0 14.3 2.6 8.0 5.6 Untreated 55.3 21.6 0 0 a Stand count values represent the average number of plants in 8 feet of row b Ratings based on 0-10 scale. 0 = no control or injury. 10 = perfect control or very severe injury. Injury rating reflects retardation and vigor in the growth of sesame. Stand count a Sesame Barley

Carbuthioate had sesame injury but had fairly good barley control. In the US in California, Fischer (1971) summarized the work that had been done between 1967 and 1970 in the San Joaquin valley to include the results of St Andre (1969, 1970a, and 1970b). In that area the concept was to grow sesame double cropped after barley or other cereals, and thus the emphasis was on controlling volunteer grasses. He summarized the results for the years as follows:

Trade name R-12001 Active ingredient Carbothiote Lbs/ac evaluated 3.0/6.0 Sesame tolerance Poor Barley control Poor

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POST summary: No known research.

CARFENTRAZONE (Aim)

PRE summary: No known research. POST OTT summary: No known research. POST DIR summary: Selective to sesame with minor reduction in yield. Needs more research before using in farmer fields. In further 2007 testing. In the US in Texas, Grichar et al. (2006) experimented with POST DIR treatments in Uvalde and Lubbock in 2006. The herbicides were applied 2" and 6" from the ground on both sides of the stem when the plants were about 18" tall in the juvenile stage. The treatments were replicated 3 times. In Uvalde the experiment was under a lateral pivot with extreme variation. As a result the yield data was taken by cutting a sample within the treatment and a sample in the adjacent untreated row. The yield below is a percent of the treated row divided by the untreated row. The Lubbock experiment was rainfed with some variation between rows, and the percentage yield below represents the treatment plot divided by the check plot. In both locations the day after planting, a PRE treatment of metolachlor plus glyphosate was sprayed over the fields. There was no weed pressure in either location since the purpose of the initial experiment was to find herbicides that would be selective to sesame.

Active ingredient Carfentrazone Rate lbs/ ac 0.016 Height of applic 2" 6" Stunting Lub 0 5 Uva Yield % of check Lub Uva 99 91 88 88

There was little damage to the sesame and little yield reduction. The testing is continuing in 2007. Harvest aid summary: Initial research shows that it does not dry down the sesame faster than normal, but it may be good as an additive to kill tough weeds such as morningglory. Needs much more research before farmer use.

CHLORAMBEN (Amiben)

Out of production in US PRE summary: Mixed results with some rates selective and others toxic to sesame, and erratic weed control. In the US, Culp and McWhorter (1965) cited Santelmann et al. (1963) who found Amiben at 4 lb/ac reduced yields. In Venezuela, Montilla (1964) had one experiment with Amiben (chloramben). The herbicide was applied PRE. Treatment Dose/ha Broad cont Grass cont Sesame germ Amiben 2l 20 49 Good

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Dose/ha Broad cont Grass cont Sesame germ 4l 22 61 Regular 8l 12 77 Regular Amiben had little weed control and the sesame germination was not as good as with other treatments. In the US in California, St Andre (1969) conducted PPI trials under furrow irrigation, planted 10 Jun. Variety was Baco planted at 2.5 lbs/ac. The stand counts were done 5 Jun and the ratings 10 Jun.

Visual rating b Herbicide Rate Barley Sesame lb/ac control injury Amiben (chloramben) 3.0 59.6 18.3 0 0 Untreated --55.3 21.6 0 0 a Stand count values represent the average number of plants in 8 feet of row b Ratings based on 0-10 scale. 0 = no control or injury. 10 = perfect control or very severe injury. Injury rating reflects retardation and vigor in the growth of sesame. Stand count a Sesame Barley

Treatment

Chloramben had no sesame injury but did not control the barley. In the US in California, St Andre (1970a) conducted PPI trials under furrow irrigation, planted 14 May. Variety was 215 (semi-shattering). Evaluated 2 Jun.

Herbicide Rate Sesame Grass lb/ac Amiben (chloramben) 4.0 55.0 4.0 1.3 63.6 Amiben + 3.0 25.6 1.3 0 9.6 CIPC (chlorpropham) 2.0 Untreated --96.0 6.6 1.3 58.3 a Stand count values represent the average number of plants in 8 feet of row b Ratings based on 0-10 scale. 0 = no control or injury. 10 = perfect control or very severe injury. Injury rating reflects retardation and vigor in the growth of sesame. Stand count a Pigweed Mustard Visual rating b Weed Sesame control injury 1.0 2.0 8.6 5.0 0 0

Chloramben by itself did not provide good weed control but did not injure the sesame significantly. With CIPC it did control the weeds, but injured the sesame more. In the US in California, Fischer (1971) summarized the work that had been done between 1967 and 1970 in the San Joaquin valley to include the results of St Andre (1969, 1970a, and 1970b). In that area the concept was to grow sesame double cropped after barley or other cereals and thus the emphasis was on controlling volunteer grasses. He summarized the results for the years as follows:

Trade name Amiben Active ingredient Chloramben Lbs/ac evaluated 3.0/4.0 Sesame tolerance Good Barley control Poor

Their overall evaluations was that chloramben was well tolerated by sesame but failed to control the weeds when PPI. In the US, in California, St Andre (1973) conducted PPI trials under furrow irrigation, planted 15 May. Variety was 247 (nonshattering). Evaluated 14 Jun. Note that the stands are much lower than the other St Andre testing. Nonshattering (indehiscent) lines have much less vigor than semi-shattering or shattering lines.

Herbicide Amiben (chloramben) Rate lb/ac 1.0 Sesame vigorb 9.8 Sesame 15.0 Stand count a Mustard Japanese millet 10.5 1.5 Pigweed 7

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Stand count a Herbicide Rate Sesame Sesame Mustard Japanese Pigweed lb/ac vigorb millet 3.0 10 15.5 7.0 12.7 18 Untreated --10 12.2 7.5 5.5 23 a Stand count values represent the average number of plants in 8 feet of row in 4 replications except for the pigweed which was only present in the 3rd replication. b Vigor evaluation is based on a 0-10 scale with 0 = very poor vigor and 10 = vigorous growing plants.

Chloramben had little effect on the sesame stand or vigor, but did not control the weeds as well as other treatments. In Egypt, Hussien et al. (1983) studied chloramben PRE. Two checks were used ­ one hand-hoed and the other with weeds. Chloramben was good on annual broadleaves. Chloramben at 0.87 kg/ha was among the most harmful treatments; however, it provided a significant increase in seed yield/ha by 57% while at 0.58 kg/ha increased the yield by 38%. Increase in seed yield by handhoeing was about 30% compared to the unweeded check. Seed oil content of sesame was not affected. POST summary: No known research.

CHLORIMURON (Classic)

PRE summary: No known research POST OTT summary: Toxic to sesame with substantial production reduction, but did not kill the sesame. In the US in South Texas, Grichar and Langham (2003) conducted a POST OTT test. A 5 ft swath of herbicides was sprayed across three rows of five lines leaving 15 ft of each row untouched to allow a direct within row comparison of the effects of the treatments. The herbicides were sprayed over the top in the juvenile stage when the plants were about 18" tall. There was a dual purpose: (1) find herbicides that were selective to sesame and (2) find herbicides that would control volunteer sesame in other crops. In this test, there were no weeds since the main thrust of the study was to look at the effects of the herbicide on the sesame. There were no replications in that the idea was to take the better lines and test them in Grichar et al. (2007). At the end of the ripening phase, the plots were evaluated in terms of percentage production compared to the untouched plants in the same row.

Treatment Chlorimuron Rate 0.5x 1.0x Average S26 50 50 37 S27 70 80 49 S28 50 50 37 S29 60 60 48 132 50 30 31 Average 56 54 40

This was one of the better treatments but there was still too much production reduction. Note that Sesaco 27 had less damage than the other varieties. Could selective varieties be developed? POST DIR summary: No known research.

CHLOROXURON (Tenoran)

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Out of production in US

PRE summary: Toxic to sesame, but did not kill sesame. In the US in California, St Andre (1970b) conducted PPI (5-6.3 cm) trials under furrow irrigation, planted 25 Jun. Stand counts were done 14 Jul and the ratings 18 Jul. The barley was harvested, disked in, listed, and preirrigated. Herbicides were applied and incorporated in the same operation with planting.

Visual ratingb Herbicide Rate Barley Sesame lb/ac control injury Tenoran (chloroxuron) 1.5 6.3 13.6 5.3 3.0 3.0 0.6 5.0 8.6 9.3 Untreated --81.0 14.0 1.6 0.6 a Stand count values represent the average number of plants in 8 feet of row b Ratings based on 0-10 scale. 0 = no control or injury. 10 = perfect control or very severe injury. Injury rating reflects retardation and vigor in the growth of sesame. Stand counta Sesame Barley

Chloroxuron reduced the sesame stand substantially and only had moderate barley control. In the US in California, Fischer (1971) summarized the work that had been done between 1967 and 1970 in the San Joaquin valley to include the results of St Andre (1969, 1970a, and 1970b). In that area the concept was to grow sesame double cropped after barley or other cereals and thus the emphasis was on controlling volunteer grasses. He summarized the results for the years as follows:

Trade name Tenoran Active ingredient Chloroxuron Lbs/ac evaluated 1.5/3.0 Sesame tolerance Poor Barley control Poor

POST summary: No known research.

CHLORPROPHAM ­ CIPC (Furloe, Chlor-IPC)

PRE summary: Mixed results with some tests toxic to sesame and others selective to sesame. In Venezuela, Mazzani (1957) tried several PRE herbicides and found that Cloro IPC (chlorpropham) at rates between 0.6 and 1.2 kg/ha controlled the weeds. In the US in Mississippi, Culp and McWhorter (1965) cited Culp and Holstun (1958) that chlorpropham (CIPC) at 4 and 8 lb/ac gave adequate weed control without apparent crop injury. In the US in Virgina, Culp and McWhorter (1965) cited Chappell (1959) that chlorpropham (CIPC) at 6 lb/ac caused little or no crop injury to sesame grown. In the US in South Carolina, Culp and McWhorter (1965) cited Martin and Crawford (1963) who reported that chlorpropham (CIPC) had been used successfully for a number of years as a broadcast PRE treatment on sesame. In the US in Mississippi, Culp and McWhorter (1965) performed several experiments over 3 years. In the greenhouse 13 herbicides were tried at different rates on sesame and four different weeds. They concluded that although pebulate (PEBC) and chlorpropham (CIPC) both provided good weed control and had 15% or less injury on the sesame that CIPC was chosen for further

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experiments because it could be readily applied with conventional farm equipment. In a 1961 experiment CIPC was used at different rates with the following results.

Rate Weed rating a Sesame rating a lb/ac 6 90 2 8 95 11 10 95 4 12 98 2 14 98 2 16 100 11 32 100 8 0 3 6 a 0 = no injury, 100 = complete kill Yield lbs/ac 790 bc 880 ab 830 abc 900 ab 600 c 820 abc 670 bc 1060 a

All rates provided excellent annual weed control with essentially no visible injury to sesame, even when applied at 32 lb/ac. Yields on all treated plots were lower than in the check plots. The reason for lack of correlation between yields and rates of herbicide is not clear. Some other factors must have caused these differences. The rainfall was adequate, but the stand was probably too thick for maximum production. Also the experimental area was more variable than desirable. In 1963 CIPC at different rates was tried on 3 planting dates with the following results:

Rate lb/ac 6 9 12 0

a

May 3 78 85 93 0

Weed rating a May 15 85 99 99 0

Jun 1 83 89 94 0 Average

May 15 1700 1740 1720 1710 1720

Yield lbs/ac Jun 1 1220 1210 1110 1120 1170

Average 1460 1480 1420 1420 1440

0 = no injury, 100 = complete kill

They concluded that CIPC was highly selective for PRE use in sesame. Optimum rates are similar to those currently recommended for weed control in cotton and other crops. In the US in California, St Andre (1969) conducted PPI trials under furrow irrigation, planted 10 Jun. Variety was Baco planted at 2.5 lbs/ac. The stand counts were done 5 Jun and the ratings 10 Jun.

Herbicide Rate lb/ac 4.0 4.0 Stand count a Sesame Barley Visual rating b Barley Sesame control injury 10.0 6.0 10.0 6.3

CIPC (chlorpropham) 15.6 0 PPG-116 16.6 0 (chlorpropham) Untreated --55.3 21.6 0 0 a Stand count values represent the average number of plants in 8 feet of row b Ratings based on 0-10 scale. 0 = no control or injury. 10 = perfect control or very severe injury. Injury rating reflects retardation and vigor in the growth of sesame.

Chlorpropham had sesame injury but had complete weed control. In the US in California, St Andre (1970a) conducted PPI trials under furrow irrigation, planted 14 May. Variety was 215 (semi-shattering). Evaluated 2 Jun.

Herbicide CIPC (chlorpropham) Amiben (chloramben) + CIPC Rate lb/ac 4.0 3.0 2.0 Sesame 2.0 25.6 Stand count a Pigweed Mustard 0 1.3 0 0 Grass 0 9.6 Visual rating b Weed Sesame control injury 10 9.3 8.6 5.0

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Untreated --96.0 6.6 1.3 58.3 0 a Stand count values represent the average number of plants in 8 feet of row b Ratings based on 0-10 scale. 0 = no control or injury. 10 = perfect control or very severe injury. Injury rating reflects retardation and vigor in the growth of sesame.

0

CIPC reduced sesame stands substantially, injured the sesame, but had very good weed control. In the US in California, St Andre (1970b) conducted PPI (5-6.3 cm) trials under furrow irrigation, planted 25 Jun. Stand counts were done 14 Jul and the ratings 18 Jul. The barley was harvested, disked in, listed, and preirrigated. Herbicides were applied and incorporated in the same operation with planting.

Visual ratingb Herbicide Rate Barley Sesame lb/ac control injury CIPC (chlorpropham) 3.0 27.6 0.6 9.3 4.0 Untreated --81.0 14.0 1.6 0.6 a Stand count values represent the average number of plants in 8 feet of row b Ratings based on 0-10 scale. 0 = no control or injury. 10 = perfect control or very severe injury. Injury rating reflects retardation and vigor in the growth of sesame. Stand counta Sesame Barley

CIPC reduced the sesame stand substantially but had very good barley control. In the US in California, Fischer (1971) summarized the work that had been done between 1967 and 1970 in the San Joaquin valley to include the results of St Andre (1969, 1970a, and 1970b). In that area the concept was to grow sesame double cropped after barley or other cereals, and thus the emphasis was on controlling volunteer grasses. He summarized the results for the years as follows:

Trade name CIPC PPG-116 Active ingredient Chlorpropham Chlorpropham Lbs/ac evaluated 3.0/4.0 4.0 Sesame tolerance Poor Poor Barley control Good Good

Their overall evaluation was that chlorpropham effectively controlled the barley but severely reduced the sesame stand when incorporated preplant. In the US in California, St Andre (1978) conducted PPI trials (5-6.3 cm) under furrow irrigation, planted 22 May. Weeds present were barley, ground cherry, sowthistle, pigweed, and lambsquarter. Variety was Lucidi.

Herbicide Furloe 124 (chlorpropham) Lasso (alachlor) + Furloe 124 (chlorpropham) Prefar (bensulide) + Furloe 124 (chlorpropham) Dual (metolachlor) + Furloe 124 (chlorpropham) Untreated

a b

Rate lb/ac 2.0 2.0 2.0 4.0 2.0 2.0 2.0 ---

Vigor 7.7 7.7

a

Grasses 6/13 9.5 9.7

Weed control b Grasses Broadleaf 6/22 6/13 9.5 10 9.5 10

Broadleaf 6/22 7.25 9.0

8.5

10

9.75

10

8.0

8.2 8.2 9.7

7.2 7.2 0

7.0 7.0 .75

9.5 9.5 5.5

5.5 5.5 5.75

Vigor scale ­ 0-10 with 0 = no vigor, 10 = excellent vigor Weed control scale 0-10 with 0 = no control, 10 = perfect control

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Chlorpropham had a slight reduction in sesame vigor, but in all combinations had good weed control. The combination with metolachlor did not prevent broadleaves from coming up later in the experiment. POST summary: No known research.

CHLORSULFURON (Glean)

PRE summary: No known research, but mixed results in planting sesame after herbicide used in previous cereal crop. In the US, there are many wheat farmers that apply sulfuron products late in the wheat crop to control broadleaf weeds. There are been mixed results in planting sesame after these products. POST summary: No known research.

CHLORSULFURON PLUS METSULFURON METHYL (Finesse)

PRE summary: No known research, but mixed results in planting sesame after herbicide used in previous cereal crop. In the US, there are many wheat farmers that apply sulfuron products late in the wheat crop to control broadleaf weeds. There are been mixed results in planting sesame after these products. POST summary: No known research.

CHORTHAL-DIMETHYL ­DCPA (Dacthal, Prothal, Shamrox)

PRE summary: Toxic to sesame except at low rates. In the US, Culp and McWhorter (1965) cited Santelmann et al. (1963) who found slight phytotoxicity and yield reduction with chlorthal-dimethyl (DCPA) at low rates, but DCPA at 12 lb/ac reduced yields. In the US in South Carolina, Culp and McWhorter (1965) cited Martin and Crawford (1963) who reported that chlorthal-dimethyl (DCPA) caused slight to severe damage, but when they were tried at lower rates none caused visible plant injury and all gave weed control essentially equivalent to that obtained with CIPC. In the US in California, Fischer (1971) summarized the work that had been done between 1967 and 1970 in the San Joaquin valley to include the results of St Andre (1969, 1970a, and 1970b). In that area the concept was to grow sesame double cropped after barley or other cereals, and thus the emphasis was on controlling volunteer grasses. He summarized the results for the years as follows:

Trade name Dacthal Active ingredient Chorthal-dimethyl (DCPA) Lbs/ac evaluated 8.0 Sesame tolerance Poor Barley control Erratic

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In Australia in Queensland, Schrodter and Rawson (1984) evaluated PRE herbicides on sesame grown under weed free and weedy conditions in 3 experiments over two years. The following were the results of the first two experiments:

Herbicide Chorthal-dimethyl (PRE) Weed free control 251 b 385 b Weedy control 322 a 431 ab a 1000s/ha b Means not followed by a common letter differ significantly (P<0.05) c Experiment says PRE but probably PPI d Measured 29 days after planting Rate kg/ha 7.5 15.0 Number of plants a 34 ad 29 bcd 59 a 52 ac Yield kg/ha 147 bd 102 cd 431 a 55d Number of plants Yield kg/ha Plant height cm d

18 abc 20 a

The results of experiment 1 were as follows: · Chlorthal-dimethyl caused severe visible damage, and thus was not planted in Experiment 2. The lower rate of chorthal-dimethyl was not as bad as the higher rate · Yield in the weedy control was reduced 87% when compared to the weed free control. The weed free control significantly outyielded all the treatments except for the high rate of alachlor. POST summary: No known research.

CLETHODIM (Select Max)

Sesame use: Used in commercial fields as POST. US label for Select Max. The herbicide can be sprayed at all stages except during flowering. PRE summary: No known research. POST OTT summary: Selective to sesame and good grass control. With the increased use of glyphosate, tanks and hoses must be thoroughly cleaned to prevent glyphosate residues being applied with the clethodim. In the US in South Texas, Grichar and Langham (2003) conducted a POST OTT test. A 5 ft swath of herbicides was sprayed across three rows of five lines leaving 15 ft of each row untouched to allow a direct within row comparison of the effects of the treatments. The herbicides were sprayed over the top in the juvenile stage when the plants were about 18" tall. There was a dual purpose: (1) find herbicides that were selective to sesame and (2) find herbicides that would control volunteer sesame in other crops. In this test, there were no weeds since the main thrust of the study was to look at the effects of the herbicide on the sesame. There were no replications in that the idea was to take the better lines and test them in Grichar et al. (2007). At the end of the ripening phase, the plots were evaluated in terms of percentage production compared to the untouched plants in the same row.

Treatment Clethodim Rate 0.5x 1.0x Average S26 100 100 37 S27 100 100 49 S28 100 100 37 S29 100 100 48 132 100 100 31 Average 100 100 40

The clethodim had no effect on the sesame and can be used as a grass herbicide. In the US, the first author has seen mixed results with Clethodim:

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· Clethodim has a faster and more lasting kill of johnsongrass than the other grass herbicides. · In 2003, clethodim was applied by a ground rig on one field at the mid bloom stage, and the plants were shut down on flowering for almost two weeks. The plants then again began to put on flowers and capsules, but never fully recovered compared to the plants near some of the edges that never were sprayed. Similar results were seen in the pre-reproductive stage when applied by a ground rig, but the plants recovered better and the damage could not be seen at the end of the crop. In previous experiments Grichar had never seen any effect on the sesame, and thus it was hypothesized that the crop oil did the damage instead of the clethodim. Grichar and Langham then applied every permutation from 0 to 3 times recommended rate of the crop oil and clethodim to a nursery in the mid bloom stage, and no effects were seen. It was concluded that the two problems had been flukes. · In 2004, clethodim was applied to a field by air in the mid bloom stage and the same results were seen, but not as severe as in 2003. Another application by a ground rig in the prereproductive stage again set back the sesame, but the damage could not be seen at the end. · In 2005, Grichar and Langham theorized that the triple application experiment might have been applied in a later stage and thus repeated the experiment of tripling the recommended rate at the same stage as the 2003 and 2004 fields and again no effects were seen in 2005. In observing sesame next to Roundup Ready cotton, the same symptoms were seen on the sesame near the cotton where there had been drift. By this point it was theorized that perhaps there were glyphosate residues in the tanks of the farmers and commercial applicators. · In 2006, there were experiments in the early bloom stage by Grichar, Dotray, and Langham in Uvalde and Lubbock using traces of glyphosate mixed into the glyphosate while again testing the clethodim up to the 3x rate. No damage was seen in the pure clethodim treatments, but the crop damage that had been seen in 2003 and 2004 was repeated in the replications with glyphosate as a trace. The conclusion was that as more farmers use glyphosate as their primary method of weed control, there is a build-up of glyphosate in the tanks. In talking to farmers, many leave glyphosate in their tanks between applications and do perfunctory cleaning prior to other chemicals. It is theorized that these residues then dissolve in the clethodim causing the damage. · An application during flowering using a quarter rate of clethodim and three quarters of fluazifop-P had excellent johnsongrass kill and no damage to the sesame. · Appling clethodim when sesame is not flowering has not had any problems. POST DIR summary: No known research, but logically if the grass weeds are short, a POST DIR application would allow contact with the small weeds in the seed line which are protected by the sesame plants from an over the top application. Clethodim characteristics: (Anon 1994, 1998) · Other crop uses: Has been applied as a POST for control of many annual and perennial grasses. An oil adjuvant is needed for maximum efficacy. Has no activity against broadleaf weeds and sedges. · Description: Clear, amber, viscous liquid. · Symptomology: Growth ceases soon after application with young and actively growing tissues affected first. Leaf chlorosis and eventually necrosis develop 1-3 weeks after application. Older leaves often turn purple, orange, or red before becoming necrotic. · Absorption/translocation: It penetrates the cuticle within 1 hour of application and subsequent rainfall does not reduce its activity. Little information is available on clethodim translocation. Presumably it acts similar to sethoxydim. · Mechanism of action: Inhibition of fatty acid synthesis prevents the building of new membranes required for cell growth.

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· Sorption: Weakly adsorbed to soil. · Transformation: - Photodegradation: Half-life was 1.7 days on a sandy loam in natural sunlight. - Other degradation: Hydrolosis half-lives varied from 28 days to 310 days depending on pH. · Persistence: Non-persistent in soil with a half-life of about 3 days. · Mobility: Not available · Volatilization: Negligible losses. · Miscellaneous information:

Common name Trade name Date Avg rate (lbs/ac) LD50 rat (mg/kg) Clethodim Select 1991 0.125 1,360 Current sample of label: http://www.valent.com/productdocs.asp?industry=2 ­ refer to basic label and supplemental label for sesame.

Using the sample label above for Select Max, there are rotational restrictions from immediate to 18 months depending on the crop and the amount of the herbicide used. The following are the restrictions for the common crops in the sesame growing areas in the US as of 24 July 07, but refer to the current label for current restrictions. There is a waiting period of 30 days after last application for crops not on the label. The label lists alfalfa, cotton, peanuts, and soybeans.

CLOMAZONE (Command)

PRE summary: Toxic to sesame, but does not prevent all germination. In Argentina in Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3 replications. There were 3 rains before emergence. The PRE test populations and weed control are as follows:

Weed control a 19 DDA b Herbicide Command

a a

30 DDA

Active ingredient Rate/ha Stand Ama Rha Ama Rha Clomazone 2.0 l 1.3 50 75 65 80 Clean check 4.1 100 100 100 100 Weedy check 3.2 0 0 0 0 a Weed control with 0 = no control and 100 = complete control. Ama = Amaranthus quitensis and Rha = Raphanus sativus b DDA = days after application

There were four ratings done 19, 30, 60, and 88 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight of capsules in the center of the capsule zone. The number of seeds were counted and the seed weight per capsule (SWC) and was taken. The PRE data was as follows:

19 DDA Clomazone 10 Clean check 83 Weedy check 77 a DDA = days after application Active ingredient 30 DDA 18 87 77 60 DDA 45 88 78 88 DDA 42 82 72 Yield (g/m) 33.1 a 59.9 de 53.8 bcde W100 (g) 0.265 0.284 0.297 Sd/cap 67 71 69 SWC (g) 0.178 0.202 0.205

Clomazone was toxic to sesame in reducing yields, but it did not kill the sesame. It did not provide good weed control.

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POST summary: No known research.

CLOPYRALID (Lontrel)

PRE summary: Initial results indicate potential use at low rates. In Australia in the Northern Territories, M. Bennett (2007) stated that the research had concentrated on summer grass control. Since 1995 herbicide research has evaluated Lontrel (clopyralid). Low rates of chemical applied PRE show promise but require further evaluation. POST summary: Proposed research.

CLORANSULAM (FirstRate)

PRE summary: Toxic to sesame with substantial reductions in stand and yield and severe injury. In the US in Texas, Grichar and Dotray (2007) conducted PRE and POST OTT studies in two locations (Yoakum and Lubbock) in 2004 and 2005. The data from the PRE tests was as follows:

Stand reduction b Injury b Yield c Rate Weed control 2004 2005 2004 2005 2005 Treat kg/ha AMATU BRAPP Lub Yoa Yoa Lub Yoa kg/ha Check 0 0 0 0 0 0 0 380 Cloransulam 0.04 90 30 100 94 82 100 18 104 LSD (0.10) 15 28 40 25 29 29 18 217 a Bayer code for weeds: AMATU (Amaranthus tuberculatus) tall waterhemp, BRAPP (Brachiaria platyphylla) broadleaf signalgrass b Stand reduction and injury index: 0 = no stand reduction or sesame injury; 100 = complete stand reduction or plant death c Weed control and sesame yield taken at the Yoakum location only

a, c

They concluded that cloransulam is not a good PRE herbicide for sesame. POST OTT summary: Toxic to sesame with severe injury and reduction in yield, but did not kill the sesame. In the US, Grichar and Dotray (2007) conducted POST OTT studies in two locations in Texas (Yoakum and Lubbock) in 2004 and 2005. The herbicides were applied in the pre-reproductive stage when the plants were about 60 cm tall. The Lubbock trials were virtually weed free while there were weeds in the Yoakum trials. The data from the tests was as follows:

Sesame injury (%) a Yield (kg/ha) Rate 2004 2005 2004 2005 Treatment b kg/ha Lub Yoa Lub Yoa Lub Lub Yoa Check 0 0 0 0 125 1,008 314 Cloransulam 0.02 58 72 25 45 23 799 284 LSD (0.10) 11 36 20 105 226 a Injury index: 0 = no sesame injury; 100 = complete plant death. Ratings taken 6-8 wks after herbicide application b All herbicides included a non-ionic surfactant added at 0.25% v/v or a crop oil concentrate added at 1 qt/ac.

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Their conclusions were as follows: · In Lubbock where there were no weeds, the treatment reduced the yield, while in Yoakum, the treatment was one of the few treatments that reduced the yield. · Cloransulam caused severe injury in most of the trials. POST DIR summary: No known research.

DICAMBA (Clarity)

PRE summary: No known research. POST OTT summary: Toxic to sesame with severe yield reduction, but did not kill the sesame. In the US in South Texas, Grichar and Langham (2003) conducted a POST OTT test. A 5 ft swath of herbicides was sprayed across three rows of five lines leaving 15 ft of each row untouched to allow a direct within row comparison of the effects of the treatments. The herbicides were sprayed over the top in the juvenile stage when the plants were about 18" tall. There was a dual purpose: (1) find herbicides that were selective to sesame and (2) find herbicides that would control volunteer sesame in other crops. In this test, there were no weeds since the main thrust of the study was to look at the effects of the herbicide on the sesame. There were no replications in that the idea was to take the better lines and test them in Grichar et al. (2007). At the end of the ripening phase, the plots were evaluated in terms of percentage production compared to the untouched plants in the same row.

Treatment Dicamba Rate 0.5x 1.0x Average S26 10 20 37 S27 10 20 49 S28 30 10 37 S29 40 50 48 132 20 10 31 Average 22 22 40

Dicamba severely reduced the sesame production substantially, but it did not kill the sesame. POST DIR summary: No known research.

DICHLOBENIL (Casoron)

PRE summary: Toxic to sesame. In the US in South Carolina, Culp and McWhorter (1965) cited Martin and Crawford (1963) who reported that dichlobenil at 4 lb/ac killed or damaged sesame in all tests. POST summary: No known research.

DICHLORMATE

PRE summary: Somewhat selective but not as good as other treatments.

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In India in Tamil Nadu, Subramanian and Sankaran (1977) carried out field experiments in 1975 in summer and during kharif to study the efficiency of dichlormate. It was not as effective as the other treatments. In India in Tamil Nadu, Subramanian and Sankaran (1981) conducted field experiments for 2 seasons to study the effect of PRE herbicides in controlling Trianthema portulacastrum and Cyperus rotundus in sesame. Sesame was given dichlormate at 1.25-1.5 kg/ha PRE in the monsoon season and was not as effective as other treatments. POST summary: No known research.

DICLOFOP (Hoelin, HOE 23408)

PRE summary: Difficult to evaluate because only research was mixed with methazole which can be toxic. In the US in California, St Andre (1974) conducted PPI (5-6.3 cm) trials under furrow irrigation, planted 28 May. Millet was seeded in the south half of each plot. Variety was Lucidi (shattering). Evaluated 13 Jul.

Herbicide Rate lb/ac Sesame vigor b 6/28 4.5 Sesame vigor b 7/13 5.5 Percent stand a 6/28 68.7 Percent stand a 7/13 42.5 Weed control c 7/13 7.2

Probe (methazole) + HOE 23408 (diclofop)

2.0 2.0 4.0 1.7 5.0 8.7 9.5 8.0 2.0 Untreated --9.0 9.2 93.7 90.0 4.2/3.7 a Stands are based on an estimated percentage. Note that the untreated stands are not 100%. b Vigor evaluation is based on a 0-10 scale with 0 = very poor vigor and 10 = vigorous growing plants. c Ratings based on 0-10 scale. 0 = no control. 10 = perfect control.

It is difficult to evaluate the diclofop because methazole had similar effects on the vigor and stands when tested by itself. POST summary: No known research.

DICLOSULAM (Spider, Strongarm)

PRE summary: Toxic to sesame with severe stand reduction. In the US in Texas, Grichar and Dotray (2007) conducted PRE and POST OTT studies in two locations (Yoakum and Lubbock) in 2004 and 2005. The data from the PRE tests was as follows:

Stand reduction b Injury b Yield c Rate Weed control 2004 2005 2004 2005 2005 Treat kg/ha AMATU BRAPP Lub Yoa Yoa Lub Yoa kg/ha Check 0 0 0 0 0 0 0 380 Diclosulam 0.03 99 61 100 86 96 100 26 64 LSD (0.10) 15 28 40 25 29 29 18 217 a Bayer code for weeds: AMATU (Amaranthus tuberculatus) tall waterhemp, BRAPP (Brachiaria

a, c

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platyphylla) broadleaf signalgrass Stand reduction and injury index: 0 = no stand reduction or sesame injury; 100 = complete stand reduction or plant death c Weed control and sesame yield taken at the Yoakum location only

b

They concluded that diclosulam is not a good PRE herbicide for sesame. In Argentina in Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3 replications. There were 3 rains before emergence. The PRE test populations and weed control are as follows:

Weed control a 19 DDA b Herbicide Spider

a a

30 DDA

Active ingredient Rate/ha Stand Ama Rha Ama Rha Diclosulam 30 g 0 100 85 100 95 Clean check 4.1 100 100 100 100 Weedy check 3.2 0 0 0 0 a Weed control with 0 = no control and 100 = complete control. Ama = Amaranthus quitensis and Rha = Raphanus sativus b DDA = days after application

There were four ratings done 19, 30, 60, and 88 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight of capsules in the center of the capsule zone. The number of seeds were counted and the seed weight per capsule (SWC) and was taken. The PRE data was as follows:

19 DDA Diclosulam 0 Clean check 83 Weedy check 77 a DDA = days after application Active ingredient 30 DDA 3 87 77 60 DDA 5 88 78 88 DDA 3 82 72 Yield (g/m) 59.9 de 53.8 bcde W100 (g) 0.284 0.297 Sd/cap 71 69 SWC (g) 0.202 0.205

Diclosulam was toxic to sesame by preventing germination. POST OTT summary: Toxic to sesame with substantial production reduction and severe injury, but did not kill the sesame. In the US in South Texas, Grichar and Langham (2003) conducted a POST OTT test. A 5 ft swath of herbicides was sprayed across three rows of five lines leaving 15 ft of each row untouched to allow a direct within row comparison of the effects of the treatments. The herbicides were sprayed over the top in the juvenile stage when the plants were about 18" tall. There was a dual purpose: (1) find herbicides that were selective to sesame and (2) find herbicides that would control volunteer sesame in other crops. In this test, there were no weeds since the main thrust of the study was to look at the effects of the herbicide on the sesame. There were no replications in that the idea was to take the better lines and test them in Grichar et al. (2007). At the end of the ripening phase, the plots were evaluated in terms of percentage production compared to the untouched plants in the same row.

Treatment Diclosulam Rate 0.5x 1.0x Average S26 30 30 37 S27 60 50 49 S28 30 30 37 S29 50 40 48 132 20 10 31 Average 38 32 40

Diclosulam severely reduced the sesame production.

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In the US, Grichar and Dotray (2007) conducted POST OTT studies in two locations in Texas (Yoakum and Lubbock) in 2004 and 2005. The herbicides were applied in the pre-reproductive stage when the plants were about 60 cm tall. The Lubbock trials were virtually weed free while there were weeds in the Yoakum trials. The data from the tests was as follows:

Sesame injury (%) a Yield (kg/ha) Rate 2004 2005 2004 2005 Treatment b kg/ha Lub Yoa Lub Yoa Lub Lub Yoa Check 0 0 0 0 125 1,008 314 Diclosulam 0.02 96 85 73 42 4 414 312 LSD (0.10) 11 36 20 105 226 a Injury index: 0 = no sesame injury; 100 = complete plant death. Ratings taken 6-8 wks after herbicide application b All herbicides included a non-ionic surfactant added at 0.25% v/v or a crop oil concentrate added at 1 qt/ac.

Their conclusions were as follows: · In Lubbock where there were no weeds, the treatment reduced the yield substantially, while in Yoakum, this was one of the few treatments that did not have a higher yield than the control. · The treatment caused severe injury to the sesame. POST DIR summary: No known research.

DIETHATYL (Antor, H-22234)

PRE summary: Selective to sesame and good weed control, but only one experiment. In the US in California, St Andre (1974) conducted PPI (5-6.3 cm) trials under furrow irrigation, planted 28 May. Millet was seeded in the south half of each plot. Variety was Lucidi (shattering). Evaluated 13 Jul.

Percent Weed Sesame Sesame Percent control c vigor b vigor b stand a stand a 6/28 7/13 7/13 6/28 7/13 H-22234 (diethatyl) 2.0 9.0 9.5 95.0 90.0 10.0 4.0 8.5 9.5 96.2 87.5 10.0 Untreated --9.0 9.2 93.7 90.0 4.2/3.7 a Stands are based on an estimated percentage. Note that the untreated stands are not 100%. b Vigor evaluation is based on a 0-10 scale with 0 = very poor vigor and 10 = vigorous growing plants. c Ratings based on 0-10 scale. 0 = no control. 10 = perfect control. Herbicide Rate lb/ac

Diethatyl was the best treatment in terms of little effect on the sesame stand and vigor and excellent weed control. POST summary: No known research.

DIETHYLACETANILIDE (C-10725)

PRE summary: Somewhat selective to sesame, but poor weed control.

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In the US in California, Fischer (1971) summarized the work that had been done between 1967 and 1970 in the San Joaquin valley to include the results of St Andre (1969, 1970a, and 1970b). In that area the concept was to grow sesame double cropped after barley or other cereals, and thus the emphasis was on controlling volunteer grasses. He summarized the results for the years as follows:

Trade name C-10725 Active ingredient Diethylacetanilide Lbs/ac evaluated 2.0 Sesame tolerance Fair Barley control Poor

POST summary: No known research.

DIFLUFENICAN (Brodal)

PRE summary: Somewhat toxic to sesame and not as good as other herbicides. In Argentina in Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3 replications. There were 3 rains before emergence. The PRE test populations and weed control are as follows:

Weed control a 19 DDA b Herbicide Brodal

a a

30 DDA

Active ingredient Rate/ha Stand Ama Rha Ama Rha Diflufenican 300 cc 1.3 100 85 95 85 Clean check 4.1 100 100 100 100 Weedy check 3.2 0 0 0 0 a Weed control with 0 = no control and 100 = complete control. Ama = Amaranthus quitensis and Rha = Raphanus sativus b DDA = days after application

There were four ratings done 19, 30, 60, and 88 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight of capsules in the center of the capsule zone. The number of seeds were counted and the seed weight per capsule (SWC) and was taken. The PRE data was as follows:

19 DDA Diflufenican 10 Clean check 83 Weedy check 77 a DDA = days after application Active ingredient 30 DDA 13 87 77 60 DDA 10 88 78 88 DDA 53 82 72 Yield (g/m) 42.5 abcd 59.9 de 53.8 bcde W100 (g) 0.284 0.284 0.297 Sd/cap 68 71 69 SWC (g) 0.193 0.202 0.205

Diflufenican was not as effective as other treatments. There was a substantial yield reduction and good weed control. POST OTT summary: Toxic to sesame with substantial injury, but the sesame did recover at the end. In Argentina in Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3 replications. There were 3 rains before emergence. The POST OTT herbicides were applied 19 days after planting. The weed control data was taken 13 days after application and was as follows:

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Herbicide Brodal

a

Rha a Active ingredient Rate/ha Ama a Diflufenican 100 cc 50 90 Weed-free check 100 100 Weedy check 0 0 Weed control with 0 = no control and 100 = complete control. Ama = Amaranthus quitensis and Rha = Raphanus sativus

There were three ratings done 13, 43, and 70 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight from capsules in the center of the capsule zone. The number of seeds were counted and the seed weight per capsule (SWC) and was taken. The POST OTT data was as follows:

13 43 DDAa DDA Diflufenican 55 78 Weed-free check 81 83 Weedy check 75 71 a DDA = days after application Active ingredient 70 DDA 65 78 65 Yieldg (g/m) 46.1 ab 48.4 ab 50.7 ab W100 (g) 0.300 0.300 0.300 Sd/cap 62.5 74.1 62.8 SWC (g) 0.188 0.222 0.188

Diflufenican had mixed results in weed and sesame control, but the sesame recovered fairly well at the end and the yield was close to the check. POST DIR summary: No known research.

DIFLUFENZOPYR (Distinct)

PRE summary: No known research POST OTT summary: Toxic to sesame with substantial production reduction, but did not kill the sesame. In the US in South Texas, Grichar and Langham (2003) conducted a POST OTT test. A 5 ft swath of herbicides was sprayed across three rows of five lines leaving 15 ft of each row untouched to allow a direct within row comparison of the effects of the treatments. The herbicides were sprayed over the top in the juvenile stage when the plants were about 18" tall. There was a dual purpose: (1) find herbicides that were selective to sesame and (2) find herbicides that would control volunteer sesame in other crops. In this test, there were no weeds since the main thrust of the study was to look at the effects of the herbicide on the sesame. There were no replications in that the idea was to take the better lines and test them in Grichar et al. (2007). At the end of the ripening phase, the plots were evaluated in terms of percentage production compared to the untouched plants in the same row.

Treatment Diflufenzopyr Rate 0.5x 1.0x Average S26 10 10 37 S27 50 30 49 S28 10 10 37 S29 40 40 48 132 20 10 31 Average 26 20 40

Diflufenzopyr severely damaged the production of sesame. POST DIR summary: No known research.

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DIMETHENAMID (Frontier)

PRE summary: Mixed results with good results for two years and almost complete kill in another year. In Thailand, W. Wongyai (2007, pers. commun.) applied Frontier (dimethenamid) 2 weeks before planting and PRE in her nurseries. It gave the good results for two years in the dry season, planting in December 2005 and in August 2005. But in the growing season of April it killed almost all the sesame lines. POST summary: No known research.

DINITRAMINE (Cobex)

Out of production in US PRE summary: Toxic to sesame. In Israel, Graph et al. (1985) showed that PPI application of dinitramine also caused severe crop damage. POST summary: No known research.

DINOSEB (Premerge)

Out of production in US PRE summary: Toxic to sesame by reducing the stand substantially. In Venezuela, Mazzani (1957) tried several PRE herbicides and found that Premerge (dinoseb) reduced the germination too much. POST summary: No known research.

DIPHENAMID (Dymid, Enid)

Out of production in US PRE summary: Selective to sesame in most research, but other treatments were better. In the US, Culp and McWhorter (1965) cited Santelmann et al. (1963) who found diphenamid at 3 lb/ac was safe applied one day after planting. In Venezuela, Montilla (1964) had three experiments with Dymid (diphenamid). · In the first experiment, the herbicides were applied PRE. Treatment Dose/ha Broad cont Grass cont Sesame germ Dymid 2 kg 14 58 Good 4 kg 21 68 Good 6 kg 40 70 Good

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Dose/ha Broad cont Grass cont Sesame germ 9 kg 16 92 Good Dymid was one of the best products; however in some of the replications of Dymid there was toxicity and the sesame plants did not develop well. · In the second experiment, the herbicides were applied pre-plant incorporated. They tried Treflan/Dymid (4+1, 4+2, and 6+1 l/ha). The sesame did not germinate in any of the treatments. · In the third experiment, he compared Venezuela 52 and Aceitera using Karmex and Dymid with the following results. Yield Treatment Dose/ha Broad cont Grass cont Plant height % % cm kg/ha V 5 Dymid 4 kg 83 86 133 784 2 6 kg 83 90 110 633 Check 114 450 Treatment Dose/ha Broad cont Grass cont Plant height Yield A % % cm kg/ha c Dymid 4 kg 87 87 100 867 e 6 kg 93 93 101 718 Check 105 583 Although Dymid did not have complete control of the weeds, it controlled enough to improve the yield over the check with no control. In Trinidad, Weiss (1971) cites L. Kasasian (1967, 1968) that trials over several years showed a combination of 3.3 kg/ha norea plus 3.3 kg/ha diphenamid was also less effective than 7 kg/ha of norea. He also provides the following table.

Herbicide Weedfree control Diphenamid Monolinuron + Diphenamid Rate (kg/ha) 4.5 9.0 1.1 2.2 Percent yield 100 97 79 61

Treatment

In the US in California, St Andre (1969) conducted PPI trials under furrow irrigation, planted 10 Jun. Variety was Baco planted at 2.5 lbs/ac. The stand counts were done 5 Jun and the ratings 10 Jun.

Visual rating b Herbicide Rate Barley Sesame lb/ac control injury Diphenamid 5.0 62.0 9.3 6.3 0 Untreated --55.3 21.6 0 0 a Stand count values represent the average number of plants in 8 feet of row b Ratings based on 0-10 scale. 0 = no control or injury. 10 = perfect control or very severe injury. Injury rating reflects retardation and vigor in the growth of sesame. Stand count a Sesame Barley

Diphenamid had no sesame injury but only fair barley control. In the US in California, St Andre (1970a) conducted PPI trials under furrow irrigation, planted 14 May. Variety was 215 (semi-shattering). Evaluated 2 Jun.

Herbicide Rate lb/ac Sesame Stand count a Pigweed Mustard Grass Visual rating b Weed Sesame control injury

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Diphenamid 5.0 97.0 0 1.0 0.3 9.8 Untreated --96.0 6.6 1.3 58.3 0 a Stand count values represent the average number of plants in 8 feet of row b Ratings based on 0-10 scale. 0 = no control or injury. 10 = perfect control or very severe injury. Injury rating reflects retardation and vigor in the growth of sesame.

3.0 0

Diphenamid had the least effect on the sesame stand, reasonable injury, and good weed control. In the US in California, St Andre (1970b) conducted PPI (5-6.3 cm) trials under furrow irrigation, planted 25 Jun. Stand counts were done 14 Jul and the ratings 18 Jul. The barley was harvested, disked in, listed, and preirrigated. Herbicides were applied and incorporated in the same operation with planting.

Herbicide Rate lb/ac Diphenamid 5.0 65.0 1.6 Diphenamid + 3.0 66.3 4.0 Lasso (alachlor) 1.5 Untreated --81.0 14.0 1.6 0.6 a Stand count values represent the average number of plants in 8 feet of row b Ratings based on 0-10 scale. 0 = no control or injury. 10 = perfect control or very severe injury. Injury rating reflects retardation and vigor in the growth of sesame. Stand counta Sesame Barley Visual ratingb Barley Sesame control injury 9.0 1.3 9.0 1.0

Diphenamid had a moderate stand reduction (still good stand), good barley control, and little sesame injury. In the US in California, Fischer (1971) summarized the work that had been done between 1967 and 1970 in the San Joaquin valley to include the results of St Andre (1969, 1970a, and 1970b). In that area the concept was to grow sesame double cropped after barley or other cereals, and thus the emphasis was on controlling volunteer grasses. He summarized the results for the years as follows:

Trade name Dymid or Enide Trefmid Active ingredient Diphenamide Trifluralin + Diphenamid Lbs/ac evaluated 5.0/6.0 0.25/4.0 on each Sesame tolerance Good Poor Barley control Good Good

Their overall evaluations was that diphenamid effectively controlled volunteer barley and other annual weeds without adversely affecting sesame. This was the only treatment that was good in both categories. The trifluralin affected the sesame in combination with diphenamid. In the US, in California, St Andre (1973) conducted PPI trials under furrow irrigation, planted 15 May. Variety was 247 (nonshattering). Evaluated 14 Jun. Note that the stands are much lower than the other St Andre testing. Nonshattering (indehiscent) lines have much less vigor than semi-shattering or shattering lines.

Stand count a Herbicide Rate Sesame Sesame Mustard Japanese Pigweed lb/ac vigorb millet Dymid (diphenamid) 5.0 10 16.7 9.0 1.2 3 Untreated --10 12.2 7.5 5.5 23 a Stand count values represent the average number of plants in 8 feet of row in 4 replications except for the pigweed which was only present in the 3rd replication. b Vigor evaluation is based on a 0-10 scale with 0 = very poor vigor and 10 = vigorous growing plants.

Diphenamid had little effect on the sesame stand or vigor, but it was not the best treatment for control of the weeds.

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In the US in California, St Andre (1974) conducted PPI (5-6.3 cm) trials under furrow irrigation, planted 28 May. Millet was seeded in the south half of each plot. Variety was Lucidi (shattering). Evaluated 13 Jul.

Herbicide Rate lb/ac Sesame vigor b 6/28 7.5 6.2 Sesame vigor b 7/13 8.0 7.5 Percent stand a 6/28 91.2 72.5 Percent stand a 7/13 76.2 72.5 Weed control c 7/13 6.0 10.0

Enide (diphenamid) 4.0 Enide (diphenamid) + 4.0 Lasso (alachlor) 2.0 Untreated --9.0 9.2 93.7 90.0 4.2/3.7 a Stands are based on an estimated percentage. Note that the untreated stands are not 100%. b Vigor evaluation is based on a 0-10 scale with 0 = very poor vigor and 10 = vigorous growing plants. c Ratings based on 0-10 scale. 0 = no control. 10 = perfect control.

Diphenamid by itself had some minor reduction of sesame vigor, but it did a poor job on controlling the weeds. In combination with alachlor, both reduced the stand and vigor substantially, but had excellent weed control. The vigor and stands were less than with either herbicide by itself. In Ethiopia, Brar (1979) cited Moore (1974) who studied 11 herbicides over two years and had the following results: diphenamid showed selectivity but did not have effective weed control. In India, Schrodter and Rawson (1984) cited Guar and Tomar (1978) who found that diphenamid at 4.5 kg/ha applied to previously hand weeded plots gave one of the highest yields. In the US in Arizona, Howell et al. (1984) had the following results:

Treat PPI PRE PRE PRE PPI PPI PPI PPI PRE PRE Herbicide Dymid (diphenamid) Dymid (diphenamid) Dymid (diphenamid) + Lasso (alachlor) Dymid (diphenamid) + Lasso(alachlor) Dymid (diphenamid) + Dual (metolachlor) Dymid (diphenamid) + Dual (metolachlor) Rate /ac 4.8 kg 4.8 kg 4.8 kg 3l 4.8 kg 3l 4.8 kg 3l 4.8 kg 3l Mid stunt no/no OK/no OK/no no/no no/OK no/no Mid stand OK/OK OK/OK OK/OK OK/OK OK/OK OK/OK Broadleaf control OK/OK OK/OK OK/OK OK/OK OK/OK OK/OK Grass control OK/OK OK/OK OK/OK OK/OK OK/OK OK/OK Early vigor OK/OK OK/OK OK/OK OK/OK OK/OK OK/OK

They concluded that diphenamid provides good weed control with acceptable stands and early vigor, but there was stunting in most of the treatments. In Israel, Graph et al. (1985) showed that 3.0 kg/ha diphenamid temporarily retarded crop growth. POST OTT summary: Selective to sesame with minor reduction in yield, stand, and vigor. In Australia in Queensland, Schrodter and Rawson (1984) evaluated PRE and POST herbicides on sesame grown under weed free and weedy conditions in Lockyer Valley in 4 experiments over two years. The variety Palmetto was used. The first two experiments were with PRE herbicides and the last two included POST herbicides. The POST applications were done 21 days after planting while the plants were in the third true leaf stage. The second POST experiment tried a few other POST herbicides with the following results

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Herbicide

Diphenamid Weed free control Weedy control a 1000s/ha b Scale 0-5 with 0 = majority of plants dead, 5 = all plants healthy, uniform growth. Taken 29 days after planting. c Means not followed by a common letter differ significantly (P<0.05)

Rate kg/ha 6.0

Number of plants a 272 a c 312 a 290 a

Yield kg/ha 783 b 937 ab 492 c

Plant vigour rating b 4.7 a 5.0 a 5.0 a

The results of the experiment were as follows: Diphenamid had no effect on yield, population, or vigor. POST DIR summary: No known research.

DIQUAT (Reglone)

PRE research: No known research. POST research: No known research. Harvest aid summary: Good potential to use as a harvest aid to dry down the sesame faster. Needs much more research before farmer use.

DIURON (Karmex, Direx, Diurol.

Layby Pro mixes diuron and linuron)

Sesame use: Used in commercial fields as PRE and POST OTT and DIR by itself and in combination with other chemicals. No US label. PRE summary: As a PRE is selective to sesame and provides good weed control. At high rates, diuron may reduce yields. Continuing testing in 2007. In Venezuela, Mazzani (1957) tried several PRE herbicides and the most promising results were with Karmex at 0.6 to 1.2 kg/ha. Different combinations of PRE rates of Karmex were tried over the seed line and between the seed lines with the following results:

Treatment (kg/ha) Above seed line Between seed lines 0.6 1.2 0.8 1.6 0 1.6 Control Number of plants 12 days 20 days 41.8 (111.7%) 30.8 (83.3%) 41.4 (110.7%) 33.8 (90.4%) 41.6 (111.2%) 41.6 (111.2%) 37.4 (100%) 36.0 (96.2%) Yield kg/ha 700.8 626.8 501.4 1,071.2

Although the diuron did not have much of an effect on the plant stands, and the seedlings appeared to recover, all treatments reduced yields. However, with the amount of weeds in the test area, no weed control would have resulted in much lower yields. In the US in Mississippi, Culp and McWhorter (1965) cited Culp and Holstun (1958) that diuron at 0.75 and 1.5 lb/ac gave adequate weed control without apparent crop injury. In the US in Mississippi, Culp and McWhorter (1965) cited Culp and McWhorter (1959) that diuron at 0.9 lb/a caused chlorosis and stand reductions. Diuron at 0.7 lb/ac was non-toxic.

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In Venezuela, Montilla (1964) had two experiments with Karmex (diuron) and other herbicides. · In the first experiment, the herbicides were applied PRE. Treatment Dose/ha Broad cont Grass cont Sesame germ Karmex 1l 85 64 Good 1.5 l 86 81 Good 2l 93 82 Regular Karmex was one of the best treatments. · In the second experiment, he compared Venezuela 52 and Aceitera using Karmex with the following results. Treatment Dose/ha Broad cont Grass cont Plant height Yield V % % cm kg/ha e Karmex 1l 64 96 100 550 n Check 114 450 5 2 Treatment Dose/ha Broad cont Grass cont Plant height Yield A % % cm kg/ha c Karmex 1l 94 94 96 784 e Check 105 583 Although Karmex did not have complete control of the weeds, it controlled enough to improve the yield over the check with no control. In Venezuela, Weiss (1971) cited Mazzani (1966) diuron (1.5 kg/ha) applied PRE gave reasonable control of weeds with no effect on the crop. In Sri Lanka, Weiss cites Appendurai (1967) who found that diuron applied at a rate of 0.6 to 0.8 kg/ha gave effective control of weeds with no significant reduction in yield. In Ethiopia, Moore (1974) experimented in (a) irrigated trials at Melka Werer and (b) rain-fed trials at Homera in 1972-3 with up to 11 herbicides applied to sesame. In (b) diuron caused serious crop damage at the rates tested. In Egypt in Shandaweel, Ibrahim et al. (1988) studied the effect of 5 herbicides applied singly or in tank mixtures or hoeing on sesame crops infested with various weeds in 2 field trials in 198485. Treatments included 0.96 kg/ha diuron applied PRE individually, or as tank mixtures of alachlor or pendimethalin. Pendimethalin alone or with linuron or diuron gave excellent control of grass weeds, while linuron or diuron alone or mixed with pendimethalin effectively controlled broadleaved weeds. The best control of annual weeds and high seed yields and yield components resulted from treatment with pendimethalin alone or in tank mixtures with linuron or diuron. In Brazil in Paraiba, Beltrado et al. (1991) found that weed control with 1 kg/ha diuron enhanced seed production but mechanical weeding combined with fertilizer applications increased weed competition. In Brazil in Paraiba, Viera et al. (1998) tested the efficacy of mixtures of diuron (0.75, 1.0 and 1.25 kg/ha) with pendimethalin (1.25 kg/ha) and alachlor (at 1.44 kg/ha) as PRE herbicides. After 15 days, significantly greater phytotoxicity was observed following treatment with the highest dose of diuron plus pendimethalin (12.5%) and alachlor (21.25%). Control ranged from 97 to 99% after 30 days and from 96 to 98% after 60 days. There were no significant differences

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for the height of the 1st fruiting branch, the number of fruits per plant, and the yield between the different treatments and mowing. In Australia, a grower guide for South Burnett (Sapin et al. 2000) stated, "PRE herbicides which are used overseas and successfully in trials in Australia include diuron (Karmex)." In Mexico, a grower guide for Michoacan (Anon, 2007 recommends the use diuron as a PRE in combination with alachlor as follows: Lasso + Karmex, Alanox + Diurol, or Herbilaz crisuron (all at 2.0 lt + 0.5 kg/ha). It is mixed with 250-300 liters of water. In the US in Texas, Grichar and Dotray (2007) conducted PRE and POST OTT studies in two locations (Yoakum and Lubbock) in 2004 and 2005. The data from the PRE tests was as follows:

Stand reduction b Injury b Yield c Rate Weed control 2004 2005 2004 2005 2005 Treat kg/ha AMATU BRAPP Lub Yoa Yoa Lub Yoa kg/ha Check 0 0 0 0 0 0 0 380 Diuron 1.12 99 93 30 13 5 17 3 208 LSD (0.10) 15 28 40 25 29 29 18 217 a Bayer code for weeds: AMATU (Amaranthus tuberculatus) tall waterhemp, BRAPP (Brachiaria platyphylla) broadleaf signalgrass b Stand reduction and injury index: 0 = no stand reduction or sesame injury; 100 = complete stand reduction or plant death c Weed control and sesame yield taken at the Yoakum location only

a, c

Despite the low yield, they concluded that diuron shows a potential for use as a PRE herbicide for sesame because of the low stand reduction and injury. In the US, the first author has made the following observations: · Cotton farmers apply diuron preplant. On hailed out cotton, there has never been a problem with sesame stands on fields that had used diuron. In Australia in the Northern Territories, M. Bennett (2007) stated that the research had concentrated on summer grass control. Since 1995 herbicide research has evaluated diuron. Low rates of chemical applied PRE show promise but require further evaluation. POST OTT summary: Diuron is somewhat selective to sesame and has good weed control, but most commercial applications are made between the rows. There was some initial discoloration, but the plants recovered. In testing in POST DIR in 2007 in combination with glyphosate. In Venezuela, Mazzani (1999) cites Caraballo et al. (1986) who compared the different times of spraying using diurón 80 (1.5 liters/ha plus 0.5 liters of surfactant). The product controlled 94% of the broadleaves and 89% of the grasses. The sesame plants suffered a bit of discoloration on the lower leaves when the product was sprayed directly into the row but returned to green in a short time.

Number of days after planting

15 22 29 36 43 50 Cleaned by hand No cleaning

Plant height, cm

159 158 153 158 149 154 160 144

Yield, kg / ha

947 896 817 911 762 770 1,117 557

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Caraballo et al. (1986) did additional experimental plots that showed the best results were from using Lazo (3-4 liters/ha) as a PRE and Karmex (2 liters/ha) as a POST. Lazo dose, l / ha Plant height, cm Yield, kg / ha 6 174 1,008 5 170 833 4 172 848 3 170 810 Cleaned by hand 166 1,042 No cleaning 154 536

In Venezuela, in a grower guide, Avila (1999) states that when the plants are about 30 cm tall, Karrnex (diuron) is used at 1.5 l/ha with 2 liters of surfactant. The diuron controls the weeds and does not damage the sesame. POST DIR summary: Good results in combination with linuron. Mixed results in combination with glysophate. In further testing in 2007. In the US in Texas, Grichar et al. (2006) experimented with POST DIR treatments in Uvalde and Lubbock in 2006. The herbicides were applied 2" and 6" from the ground on both sides of the stem when the plants were about 18" tall in the juvenile stage. The treatments were replicated 3 times. In Uvalde the experiment was under a lateral pivot with extreme variation. As a result the yield data was taken by cutting a sample within the treatment and a sample in the adjacent untreated row. The yield below is a percent of the treated row divided by the untreated row. The Lubbock experiment was rainfed with some variation between rows, and the percentage yield below represents the treatment plot divided by the check plot. In both locations the day after planting, a PRE treatment of metolachlor plus glyphosate was sprayed over the fields. There was no weed pressure in either location since the purpose of the initial experiment was to find herbicides that would be selective to sesame.

Active ingredient Diuron + Glyphosate Linuron and diuron Rate lbs/ ac 0.75 0.75 1.0 Height of applic 2" 6" 2" 6" Stunting Lub 0 5 0 0 Uva Yield % of check Lub Uva 62 90 46 84 100 126 89 88

In combination with the glyphosate there was a substantial yield reduction in Lubbock, but the combination with linuron in Layby Pro is very promising. Within 2 weeks of application, there is no visual damage in combination with linuron; in combination with glyphosate, minor plants are dying and at 6" there are major plants killed. In the US, the first author has made the following observations: · In the Lubbock nursery in 2005, the farmer was using diuron on cotton and POST DIR sprayed a sesame strip (the juvenile stage while 20" tall) with morningglory with the chemicals hitting the stems of the sesame about 3" from the ground. There was no visible damage to the sesame. The existing morningglory plants were killed, but there was another flush with the next rain. Diuron characteristics: (Anon 1994, 1998) · Other crop uses: Has been used as PRE, POST, and POST DIR. It controls many annual weeds at lower rates and certain perennial weeds at higher rates. · Description: White crystalline solid, odorless

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· Symptomology: Foliar chlorosis concentrated around veins (sometimes interveinal) followed by necrosis · Absorption/translocation: Readily absorbed by roots, less so by foliage and stems. It is translocated rapidly from roots to shoots via the xylem. Little to no diuron moves basipetally out of a treated leaf via the phloem. · Mechanism of action: Inhibits photosynthesis. · Sorption: Adsorbs to OM and clay. · Transformation: - Photodegradation: Not strongly photodegraded, but losses can be significant if it remains on the soil surface for several days or weeks. - Other degradation: Microbial degradation is the primary means of dissipation from soil · Persistence: Average field half-life is 90 days. Phytotoxic residues dissipate within a season when applied at lower selective rates. At higher selective rates, residues may persist for more than 1 year. · Mobility: Moderately leachable; leaching not a problem except on soils low in OM and clay. · Volatilization: Probably insignificant losses except when it is exposed on the soil surface for several days or weeks under hot, dry conditions. · Miscellaneous information:

Common name Trade name Date Avg rate (lbs/ac) LD50 rat (mg/kg) Diuron Karmex 1950s 3.5 3,400 Current sample of label: http://www2.dupont.com/Production_Agriculture/en_US/products_services/herbicides/Direx_4L_herbicide.html

Using the sample label above for Direx 4L, there are rotational restrictions from immediate to 2 years depending on the rate, the type of application, and the following crop. Refer to the current label for current restrictions.

ENDOTHAL (Accelerate)

PRE summary: Toxic to sesame with slight to severe stunting, but did not kill sesame. In the US, Culp and McWhorter (1965) cited Tocquigny and Livingston (1953) that endothall PRE caused slight to severe stunting, and did not overcome the problem before harvest. POST OTT summary: Toxic to sesame with severe stunting, but did not kill the sesame. Culp and McWhorter (1965) cited Tocquigny and Livingston (1953) that endothall POST OTT caused severe stunting, and the plants did not overcome the stunted condition before harvest. POST DIR summary: No known research.

EPTC (Eptam)

PRE summary: Mixed results with selectivity and toxicity to sesame under different conditions. In Sri Lanka, Weiss (1971) cites Anon (1960) that Eptam gave promising results.

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In the US, Culp and McWhorter (1965) cited Santelmann et al. (1963) who found EPTC at 2 lb/ac was safe applied one day after planting. In the US in California, St Andre (1969) conducted PPI trials under furrow irrigation, planted 10 Jun. Variety was Baco planted at 2.5 lbs/ac. The stand counts were done 5 Jun and the ratings 10 Jun.

Visual rating b Herbicide Rate Barley Sesame lb/ac control injury Eptam (EPTC) 3.0 39.3 9.6 5.3 2.6 CP-53619 (EPTC) 2.0 53.3 24.0 0 0 4.0 37.3 15.6 3.3 2.0 Untreated --55.3 21.6 0 0 a Stand count values represent the average number of plants in 8 feet of row b Ratings based on 0-10 scale. 0 = no control or injury. 10 = perfect control or very severe injury. Injury rating reflects retardation and vigor in the growth of sesame. Stand count a Sesame Barley

EPTC had little sesame injury but did not control the barley. In the US in California, Fischer (1971) summarized the work that had been done between 1967 and 1970 in the San Joaquin valley to include the results of St Andre (1969, 1970a, and 1970b). In that area the concept was to grow sesame double cropped after barley or other cereals, and thus the emphasis was on controlling volunteer grasses. He summarized the results for the years as follows:

Trade name Eptam Active ingredient EPTC Lbs/ac evaluated 3.0 Sesame tolerance Poor Barley control Good

In Ethiopia, Moore (1973a, 1974) evaluated herbicides for use in sesame grown on a dark brown sandy clay loam under irrigation at Melka Werer. EPTC at 1.8 kg and 3.9 kg/ha PPI was active against Cyperus spp. but selectivity was not adequate. In Ethiopia, Moore (1973b, 1974) carried out a trial in the higher rainfall area at Setit Humera where irrigation was not necessary. EPTC PPI caused substantial damage to sesame seedlings. In Australia in the Northern Territories, a grower guide (Bennett 1998) stated, "Eptam has been used as a PRE herbicide for some broadleaf weeds." POST summary: No known research.

ETHALFLURALIN (Curbit, Sonalan)

PRE summary: Mixed results because significant reduced plant height and plant populations and yet yields compared to a weedy check were higher. Had good grass control but erratic broadleaf control. In the US in South Texas, Grichar et al. (2001a) conducted field studies from 1994 through 1997 in Yoakum and in Uvalde in 1995 to evaluate soil-applied herbicides for weed control, sesame tolerance, and yield. There were four replications. The varieties used were Sesaco 11, 17, or 18. The plant height was taken from averaging 5 plants and taken 5-7 weeks after planting. The data is as follows:

Sesame height (cm)

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Herbicide Ethalfluralin

Rate kg/ha 0.6 1.3

Applic PPI PPI

Check LSD (0.05) a WAP = weeks after planting b Significantly different from check

1994 5 WAP a 35.6 21.6 b 43.4 16.9

1995 7 WAP 43.7 b 28.2 b 131.3 31.0

1996 6 WAP 49.5 46.5 43.4 11.6

1997 5 WAP 67.4 43.2 b 70.9 14.7

Ethalfluralin significantly reduced plant height in most of the trials. The sesame population was counted 4-6 weeks after planting. The data was as follows:

Plants/m of row Herbicide Applic Ethalfluralin PPI Ethalfluralin PPI Check LSD (0.05) a Significantly different from check Rate kg/ha 0.6 1.3 1995 2.8 a 3.0 a 70.3 23.5 1996 28.5 a 11.0 a 65.3 36.1 1997 14.7 a 0.6 a 67.5 18.8

Ethalfluralin lowered the population significantly in all trials. The weed control is based on 0 = not control and 100 = complete control. The weed control data was as follows:

Herbicide Ethalfluralin Ethalfluralin Check LSD (0.05) Rate kg/ha 0.6 1.3 Applic PPI PPI Broadleaf signalgrass 70 77 0 21 Brown-top panicum 100 100 0 10 Southern cragrass 100 98 0 18 Palmer amaranth 1994 1995 58 79 0 25 98 100 0 4

Ethalfluralin provided good grass control but was erratic on broadleaf control as would be expected. The weed control data was as follows:

Rate Herbicide kg/ha Applic Ethalfluralin 0.6 PPI Ethalfluralin 1.3 PPI Check LSD (0.05) a Significantly different from check 1994 Yoakum 470 360 650 300 1995 Yoakum 870 310 1995 Uvalde 1600 a 1320 870 470 1996 Yoakum 740 680 480 450 1997 Yoakum 700 a 710 a 480 180

The data in the following table was converted to a percentage yield compared to the check, but the average did not include 1996 where all of the herbicides exceeded the yields of the check.

Rate 1994 Herbicide kg/ha Applic Yoakum Ethalfluralin 0.6 PPI 72 Ethalfluralin 1.3 PPI 55 a Significantly different from check 1995 Yoakum 1995 Uvalde 184 a 152 1996 Yoakum 154 142 1997 Yoakum 146 a 148 a Average 134 118

Although ethalfluralin affected the plant height and stand, the yields were better than the checks with no weed control in all years except for 1994. Sesame has the ability to compensate for low stands by setting branches that load up with capsules. They concluded that ethalfluralin is a good option for weed control but crop safety is a concern if the herbicide is incorporated too deep in a shallow planted crop. POST summary: No known research.

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FENOXAPROP (Whip)

PRE summary: Not effective in sesame. W. Wongyai (2007, pers. commun.) applied applied Whip 85 (fenoxaprop) in March 2007 planting PRE. She will no longer use it on sesame. POST summary: No known research.

FLUAZIFOP-P (Fusilade)

Sesame use: Used in commercial fields as a POST. No label in US. PRE summary: No known research. POST OTT summary: Selective to sesame and good grass control. In Somalia, Malik and Ramzan (1992) conducted field studies during April-June and OctoberDecember 1989, to examine the efficacy and yield of the POST herbicides Fusilade 25EC (fluazifop-P) at 3.7 l/ha as compared to hand weeding for the control of weeds infesting sesame. The results showed that all herbicides and hand weeding gave an effective level of control. In a grower guide, Avila (1999) states that for grasses, fluazifop-P at 200 to 400 cc/ha works well. In Australia in South Burnett, a grower guide (Sapin et al. 2000) stated that sesame is susceptible to, but will tolerate fluazifop (Fusilade) but it is not registered in Australia. In the US in South Texas, Grichar et al. (2001b) conducted POST OTT studies in weed free areas at Yoakum and Uvalde from 1994 to 1997. The varieties used were Sesaco 11, 17, or 18. The herbicides were applied over the top 3-4 wk after planting in Yoakum and 6 wk after planting in Uvalde. Sesame was 30-48 cm in height at the time of application. Planting dates in Yoakum were 26 May 1994, 11 July 1995, 12 July 1996, and 1 July 1997. Planting date in Uvalde was 28 April 1995. Ratings of stunting (0= no stunting and 100 = total stunting) were done 3 weeks after herbicide application as shown below.

Rate (kg/ha) Check Fluazifop-P LSD (0.05) 0.21 94 YOA 0 0 28 94 YOA 91 103 26 94 YOA 408 658 95 UVA 0 0 19 95 YOA 110 84 32 95 UVA 844 783 95 YOA 0 0 12 96 YOA 71 53 23 95 YOA 482 754 96 YOA 0 0 22 97 YOA 74 65 16 96 YOA 419 273 97 YOA 501 604 Avg 531 614 % check 116 97 YOA 0 0 12

Fluazifop-P did not stunt the sesame. The effects on plant height (cm) were as follows:

Rate (kg/ha) Check Fluazifop-P LSD (0.05) 0.21

There was some plant height reduction. The yields (kg/ha) were as follows:

Rate (kg/ha) Check Fluazifop-P 0.21

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Rate (kg/ha) LSD (0.05)

94 YOA 248

95 UVA 210

95 YOA 255

96 YOA 217

97 YOA NS

Avg

% check

The fluazifop-P did not reduce the yield and actually increased the yield by controlling the grasses. In Australiain the Northern Territories, Bennett (2003, 2007, pers. commun.): "We have no approved herbicides for sesame and need `minor crop' usage approval from the relevant authority. If grass weeds become a problem post emerge we use Fusilade (fluazifop-P) at recommended rates." In Nigeria, in a survey of agricultural crops (Anon 2004), it states, "The use of Fusilade (fluazifop-P) as a POST for weed control was reported by two benniseed farmer cooperatives." In Australia, Jim Barnes (2007, pers. commun.) stated: "My observations were that just about any post emergence grass killing herbicides were OK (we did not try them all but fluazifop-P was OK) Most of these herbicides are only active against grasses anyway so should be OK." In the US, the first author has made the following observations: · Fluazifop-P has been applied in many stages and in many ways without any damage to the sesame. It has been applied as early as the seedling stage (first true leaf) through late drydown stage. It has been applied by back-pack, ground rig, and from the air. · The only problem with fluazifop-P has been that it is not always effective against the johnsongrass if it gets too tall and is no longer growing. Although it is easy to kill johnsongrass from seeds, it is difficult to kill the rhizomes and that johnsongrass may emerge later in the season. POST DIR summary: No known research, but logically if the grass weeds are short, a POST DIR application would allow contact with the small weeds in the seed line which are protected by the sesame plants from an over the top application. Flazifop-P characteristics: (Anon 1994, 1998) · Other crop uses: Has been used as a POST. It controls most annual and perennial grass weeds including barnyardgrass, crabgrass, downy brome, panicum, foxtail, volunteer cereals, shattercane, quackgrass, and johnsongrass. It has essentially no activity on broadleaf species. An oil adjuvant is required for maximum efficacy. · Description: Light straw-colored liquid, odorless. · Symptomology: Growth ceases soon after application with young and actively growing tissues affected first. Leaf chlorosis and eventually necrosis develop 1-3 weeks after application. Older leaves often turn purple, orange, or red before becoming necrotic. · Absorption/translocation: Readily absorbed into leaves and is rainfast within about 2 hours of application. It principally translocates in the symplast (including the phloem) and accumulates in the meristematic regions of the root and shoot. However, translocation rate appears slow. · Mechanism of action: Inhibition of fatty acid synthesis prevents the building of new membranes required for cell growth. · Sorption: · Transformation: - Photodegradation: Negligible losses. - Other degradation: It is rapidly (half-life <1 week) converted to an acid which has a half-life of about 3 weeks under moist conditions in most moist solids.

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· Persistence: Average field half-life is 15 days. It occasionally controls or suppresses grass weeds germinated after application. Degree of residual activity varies with soil type and rainfall. Susceptible rotational crops can be planted 60 days after application. · Mobility: The ester form has low mobility in soil while the acid is somewhat more mobile. Neither chemical presents an appreciable risk of groundwater contamination. · Volatilization: Negligible losses. · Miscellaneous information:

Common name Trade name Date Avg rate (lbs/ac) LD50 rat (mg/kg) Fluazifop-P Fusilade 1982 0.313 4,350 Current sample of label: http://www.syngentacropprotection-us.com/pdf/labels/SCP1070AL1A0904.pdf

Using the sample label above for Fusilade DX, there are rotational restrictions from immediate to 60 days depending on the crop and the amount of the herbicide used. The following are the restrictions for the common crops in the sesame growing areas in the US as of 24 July 2007, but refer to the current label for current restrictions. Do not plant corn, rye, sorghum or wheat for 60 days after last application.

FLUCHLORALIN (Basalin)

Out of production in US Sesame use: Used in commercial fields as a PPI and PRE. No label in US. PRE summary: Selective to sesame and good weed control. In India, Ghosh and Mukhopadhyay (1980) carried out field experiments during the kharif season of 1979 that showed that fluchloralin at 0.72 kg/ha applied PRE (1 day after sowing) effectively controlled weeds and increased the seed yield of the crop to a level comparable to that obtained on weed-free controls. No advantage was gained by hand-weeding the fluchloralin treated plots 30 days after sowing. Higher rates of fluchloralin injured the crop. In India, Bansode and Shelke (1991) assessed six weed control treatments (an unweeded control, hand weeding (HW) + hoeing 3 weeks after sowing (WAS), PPI of 0.68 or 1.12 l/ha fluchloralin in field trials during the kharif of 1988 with sesame (cv. Punjab-1 and T-85). Lowest yield (75 kg) was obtained with cv. T-85 and fluchloralin which was phytotoxic to this cultivar. In India in Madhya Pradesh, Sootrakar et al. (1995) conducted a field experiment in 1991-92. Hand weeding 25, 40 and 55 days after sowing (DAS) produced the highest mean seed yield of 0.77 t/ha, followed by 0.69 t obtained with PPI of 2 l/ha fluchloralin + hand weeding 25 DAS. The application of 2 l/ha fluchloralin PPI alone produced a mean yield of 0.66 t and the highest net return. In India in Madhya Pradesh, Chauhan and Gurjar (1998) carried out a field experiment during 1991 and 1992 to study mechanical and chemical weed control in sesame on sandy loam soil. Mechanical and chemical treatments significantly reduced dry matter production by weeds compared with the untreated control. Three hand-weedings (20, 40 and 60 days after sowing) and pre-sowing application of 0.75 kg/ha Basalin (fluchloralin) both gave highest yield, followed 2 hand-weeding at 20 and 40 days. In India in Haryana, Punia et al. (2001) conducted an experiment on sandy loam soil during kharif 1999 and 2000, to investigate the efficacy of herbicides against weeds in sesame (cv. HY-1). Treatments included fluchloralin at 0.75, 1.0 and 1.25 kg/ha and integration with one hoeing at 4

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weeks after sowing (WAS). Fluchloralin was applied PPI in 2-3 cm top soil before sowing. On an average, season long weed competition caused 61% reduction in seed yield. Two hoeings at 3 and 6 WAS, integration of either fluchloralin, pendimethalin or trifluralin at 1.0 kg/ha with one hoeing at 4 WAS were significantly better in terms of weed control efficiency and seed yield compared to one hoeing at 4 WAS or herbicides used alone. In India in Uttar Pradesh, Om et al. (2001) investigated the effects of N fertilizer application and weed control measures on sesame during 1995 and 1996. Treatments consisted of N levels, i.e. 0, 30, 60 and 90 kg/ha, and weed control treatments, i.e. weedy control, hand weeding 3 weeks after sowing, PREPLANT application of fluchloralin (1.0 kg/ha) + hand weeding,. N fertilizer rate did not significantly affect the weed population. Aside from exhibiting the highest weed-killing efficiency, PREPLANT application of fluchloralin + hand weeding recorded the highest values for seed yield and most yield-contributing characters. In India in Rajasthan, Dungarwal et al. (2003) conducted a field experiment during the kharif seasons of 1997 and 1998 to evaluate the relative efficacy of fluchloralin applied alone or in combination with one hoeing at four weeks after sowing (WAS) to control weeds in sesame (cv. TC 25). On average, season-long weed competition caused 50% reduction in seed yield. Integration of fluchloralin at 1.0 kg/ha or at 2.0 kg/ha with one hoeing at 4 WAS was more effective when assessed in terms of weed control efficiency and seed yield compared to their single application. Among the herbicides, alachlor and fluchoralin combined with one hoeing at 4 WAS were the best treatments. In India in Rajasthan, Yadav (2004) conducted a field experiment during the 1998 and 1999 kharif seasons on sesame (cv. RT-46) to determine a suitable integrated method for weed control. The treatments comprised: weedy control; one hand-weeding (HW) at 20 days after sowing (DAS); 2 HW at 20 and 40 DAS; PPI of 0.5 kg/ha fluchloralin; PPI of 0.75 kg/ha fluchloralin + HW at 40 DAS ; PPI of 0.5 kg fluchloralin /ha + HW at 40 DAS; PPI 0.75 kg/ha fluchloralin. The lowest weed dry matter and highest weed control efficiency, number of capsules per plant, pooled mean seed yield, gross returns, net returns, and incremental benefit cost ratio were obtained with PPI of 0.5 kg/ha fluchloralin + HW at 40 DAS treatment. In Pakistan, a grower guide (Panhwar 2005) recommends fluchloralin 0.75 kg/ha. In India in Tamil Nadu, Gnanavel and Anbhazhagan (2006) conducted a field experiment in summer 2002 to evaluate the efficacy of different PRE herbicides and herbicide along with hand weeding (HW) in controlling weeds in irrigated sesame (cv. TMV 5). The treatments included 1.5 kg/ha fluchloralin and 1.0 kg/ha fluchloralin + HW at 30 DAS, and they were not as good as other treatments. POST summary: No known research.

FLUFENACET (Radius.

Mixed with metribuzim - Axiom, Domain)

PRE summary: Toxic to sesame with severe reduction in stand and yield and too much injury. In the US in Texas, Grichar and Dotray (2007) conducted PRE and POST OTT studies in two locations (Yoakum and Lubbock) in 2004 and 2005. The data from the PRE tests was as follows:

Rate Weed control

a, c

Stand reduction b 2004 2005

Injury b 2004 2005

Yield c 2005

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Treat Check Flufenacet + metribuzim Flufenacet

kg/ha 0.14 0.21 0.84 1.68

AMATU 0 89

BRAPP 0 66

Lub 0 -

Yoa 0 74

Yoa 0 49

Lub 0 -

Yoa 0 25

kg/ha 380 305

92 69 6 97 0 57 94 78 72 100 14 54 LSD (0.10) 15 28 40 25 29 29 18 217 a Bayer code for weeds: AMATU (Amaranthus tuberculatus) tall waterhemp, BRAPP (Brachiaria platyphylla) broadleaf signalgrass b Stand reduction and injury index: 0 = no stand reduction or sesame injury; 100 = complete stand reduction or plant death c Weed control and sesame yield taken at the Yoakum location only

They concluded that flufenacet by itself and in combination with metribuzim are not viable as a PRE herbicide for sesame because of the damage to the sesame. POST summary: No known research.

FLUMETSULAM (Preside)

PRE summary: Toxic to sesame, but does not kill all the sesame. In Argentina in Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3 replications. There were 3 rains before emergence. The PRE test populations and weed control are as follows:

Weed control a 19 DDA b Herbicide Preside

a a

30 DDA

Active ingredient Rate/ha Stand Ama Rha Ama Rha Flumetsulam 90 g 2.2 85 0 80 0 Clean check 4.1 100 100 100 100 Weedy check 3.2 0 0 0 0 a Weed control with 0 = no control and 100 = complete control. Ama = Amaranthus quitensis and Rha = Raphanus sativus b DDA = days after application

There were four ratings done 19, 30, 60, and 88 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight of capsules in the center of the capsule zone. The number of seeds were counted and the seed weight per capsule (SWC) and was taken. The PRE data was as follows:

19 DDA Flumetsulam 13 Clean check 83 Weedy check 77 a DDA = days after application Active ingredient 30 DDA 17 87 77 60 DDA 47 88 78 88 DDA 43 82 72 Yield (g/m) 33.5 ab 59.9 de 53.8 bcde W100 (g) 0.269 0.284 0.297 Sd/cap 60 71 69 SWC (g) 0.161 0.202 0.205

Flumetsulam reduced yields substantially and did not control Raphanus. POST summary: Toxic to sesame with complete kill.

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In Argentina in Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3 replications. There were 3 rains before emergence. The POST OTT herbicides were applied 19 days after planting. The weed control data was taken 13 days after application and was as follows:

Herbicide Preside Active ingredient Rate/ha Ama a Flumetsulam 300 cc 100 Weed-free check 100 Weedy check 0 Weed control with 0 = no control and 100 = complete control. Rha = Raphanus sativus Rha a 100 100 0 Ama = Amaranthus quitensis and

a

There were three ratings done 13, 43, and 70 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight from capsules in the center of the capsule zone. The number of seeds were counted and the seed weight per capsule (SWC) and was taken. The POST OTT data was as follows:

13 43 DDAa DDA Flumetsulam 5 0 Weed-free check 81 83 Weedy check 75 71 a DDA = days after application Active ingredient 70 DDA 0 78 65 Yieldg (g/m) 48.4 ab 50.7 ab W100 (g) 0.300 0.300 Sd/cap SWC (g) 0.222 0.188

74.1 62.8

The flumetsulam had excellent weed and sesame control ­ there was no sesame stand left. POST DIR summary: No known research.

FLUMIOXAZIN (Valor, Sumisoya, Broadstar, Chateau)

Sesame use: Potential to use POST DIR. PRE summary: Toxic to sesame with severe reduction in stand and yield and too much injury. In the US in Texas, Grichar and Dotray (2007) conducted PRE and POST OTT studies in two locations (Yoakum and Lubbock) in 2004 and 2005. The data from the PRE tests was as follows:

Stand reduction b Injury b Yield c Rate Weed control 2004 2005 2004 2005 2005 Treat kg/ha AMATU BRAPP Lub Yoa Yoa Lub Yoa kg/ha Check 0 0 0 0 0 0 0 380 Flumioxazin 0.07 100 48 94 100 100 77 100 0 0.11 100 67 100 100 100 100 100 0 0.14 100 91 94 100 100 88 100 0 LSD (0.10) 15 28 40 25 29 29 18 217 a Bayer code for weeds: AMATU (Amaranthus tuberculatus) tall waterhemp, BRAPP (Brachiaria platyphylla) broadleaf signalgrass b Stand reduction and injury index: 0 = no stand reduction or sesame injury; 100 = complete stand reduction or plant death c Weed control and sesame yield taken at the Yoakum location only

a, c

They concluded that flumioxazin is not a good PRE herbicide for sesame.

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In Argentina in Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3 replications. There were 3 rains before emergence. The PRE test populations and weed control are as follows:

Weed control a 19 DDA b Herbicide Sumisoya

a a

30 DDA

Active ingredient Rate/ha Stand Ama Rha Ama Rha Flumioxazin 70 cc 0.2 100 95 100 99 Clean check 4.1 100 100 100 100 Weedy check 3.2 0 0 0 0 a Weed control with 0 = no control and 100 = complete control. Ama = Amaranthus quitensis and Rha = Raphanus sativus b DDA = days after application

There were four ratings done 19, 30, 60, and 88 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight of capsules in the center of the capsule zone. The number of seeds were counted and the seed weight per capsule (SWC) and was taken. The PRE data was as follows:

19 DDA Flumioxazin 0 Clean check 83 Weedy check 77 a DDA = days after application Active ingredient 30 DDA 2 87 77 60 DDA 0 88 78 88 DDA 8 82 72 Yield (g/m) 59.9 de 53.8 bcde W100 (g) 0.284 0.297 Sd/cap 71 69 SWC (g) 0.202 0.205

Flumioxazin has excellent weed control, but it also prevented sesame from germinating. POST OTT summary: Mixed results: Initial results: toxic to sesame when used with a surfactant. Somewhat selective to sesame (injured but recovers) when used without a surfactant, but does not control weeds. Potential to use to provide residual control after getting a sesame stand. Needs more research before using in farmer fields. In further testing in 2007. In Argentina in Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3 replications. There were 3 rains before emergence. The POST OTT herbicides were applied 19 days after planting. The weed control data was taken 13 days after application and was as follows:

Herbicide Sumisoya Active ingredient Rate/ha Ama a Rha a Flumioxazin 70 cc 50 90 Weed-free check 100 100 Weedy check 0 0 Weed control with 0 = no control and 100 = complete control. Ama = Amaranthus quitensis and Rha = Raphanus sativus

a

There were three ratings done 13, 43, and 70 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight from capsules in the center of the capsule zone. The number of seeds were counted and the seed weight per capsule (SWC) and was taken. The POST OTT data was as follows:

Active ingredient 13 DDAa 43 DDA 70 DDA Yieldg (g/m) W100 (g) Sd/cap SWC (g)

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Active ingredient

13 43 DDAa DDA Flumioxazin 42 83 Weed-free check 81 83 Weedy check 75 71 a DDA = days after application

70 DDA 73 78 65

Yieldg (g/m) 56.1 b 48.4 ab 50.7 ab

W100 (g) 0.288 0.300 0.300

Sd/cap 73.6 74.1 62.8

SWC (g) 0.212 0.222 0.188

Although the early weed control and sesame injury was median, at the end the sesame recovered well and there were few weeds in the plots. The Amaranthus must have been set back and allowed the sesame to canopy over. The end yields and evaluation were very comparable to the checks. In the US, the first author has made the following observations: · In the Lubbock nursery in 2005, the farmer was using flumioxazin on cotton and POST DIR sprayed a sesame strip (the juvenile stage while 20" tall) with morningglory with the chemicals hitting the stems of the sesame about 3" from the ground. There was no visible damage to the sesame. The existing morningglory plants were killed, and there was excellent control the rest of the season. POST DIR summary: Selective to sesame when used by itself. In combination with glyphosate was toxic to sesame in one location with severe yield reduction, while it improved yield in another location. Needs more research before using in farmer fields. In further testing in 2007. In the US in South Texas, Grichar et al. (2006) experimented with POST DIR treatments in Uvalde and Lubbock in 2006. The experiment is being repeated in 2007. The variety used was Sesaco 29 planted 25 May in Uvalde and 20 June in Lubbock. The herbicides were applied 2" and 6" from the ground on both sides of the stem when the plants were about 18" tall in the juvenile stage. The treatments were replicated 3 times. In Uvalde the experiment was under a lateral pivot with extreme variation. As a result the yield data was taken by cutting a sample within the treatment and a sample in the adjacent untreated row. The yield below is a percent of the treated row divided by the untreated row. The Lubbock experiment was rainfed with some variation between rows, and the percentage yield below represents the treatment plot divided by the check plot. In both locations the day after planting, a PRE treatment of metolachlor plus glyphosate was sprayed over the fields. There was no weed pressure in either location since the purpose of the initial experiment was to find herbicides that would be selective to sesame.

Active ingredient Flumioxazin + Glyphosate Rate lbs/ ac 0.063 0.75 Height of applic 2" 6" Stunting Lub 0 5 Uva Yield % of check Lub Uva 56 108 64 108

In Uvalde the combination helped the yield, but severely lowered the yield in Lubbock. Flumioxazin characteristics: (Anon 1994, 1998) · Other crop uses: Has been used as a PRE, POST, and POST DIR. It controls common ragweed, common lambsquarters, velvetleaf, pigweed (Amaranthus), black nightshade, tall and common waterhemp, and prickly sida. It aids rapid burndown and offers residual control (4 to 6 weeks) of broadleaf weeds. · Description: White crystalline solid, odorless. · Symptomology: Plants emerging from the soil become necrotic and die shortly after exposure to sunlight. Foliar contact causes rapid desiccation and necrosis of exposed plant tissues.

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· Absorption/translocation: Taken up the roots and foliage. In soil applications, root absorption is the primary action. Phloem movement is assumed to be limited because of the rapid foliar desiccation caused by this herbicide. · Mechanism of action: It is believed that flumioxazin inhibits the formation of an enzyme important in the synthesis of chlorophyll. · Sorption: Not available · Transformation: - Photodegradation: Susceptible to photodecomposition and has a half-life of 3.2 days. - Other degradation: In soils, there is microbial degradation with a half life of 11.9 to 17.5 dayss. · Persistence: The low use rate and rapid soil dissipation results in low carryover potential to rotational crops. It is not persistent in soils. · Mobility: The potential to leach in field agricultural soil is low. · Volatilization: Probably insignificant losses except where soil is warm and no activating rainfall is received for several days or weeks after application, leaving it on the soil surface. · Miscellaneous information:

Common name Trade name Date Avg rate (lbs/ac) Flumioxazin Sumisoya 1989 Current sample of label: (http://www.valent.com/productdocs.asp?industry=2). LD50 rat (mg/kg) >5,000

Using the sample label above for Valor SX, there are rotational restrictions from immediate to 18 months depending on the crop and the amount of the herbicide used. The following are the restrictions for the common crops in the sesame growing areas in the US as of 17 Jul 07, but refer to the current label for current restrictions.

Crop Alfalfa Corn, field Cotton Peanuts Rye Sorghum Soybean Wheat Up to 2 oz 6 months 1 month 1 month Immediate 4 months 1 month Immediate 1 month Up to 3 oz 10 months 1 month 2 months Immediate 4 months 1 month Immediate 2 months Up to 4 oz 12 months 4 months 4 months 4 months 12 months 4 months 4 months 4 months 6-12 oz 18 months 9 months 9 months 9 months 18 months 9 months 9 months 9 months

FLUOMETURON (Cotoran, Kotoran, Lanex)

Sesame use: Used in commercial fields as a PRE. No US label. PRE summary: Selective to sesame, but there are other herbicides that were judged better. Further testing should be done. In India in Tamil Nadu, Subramanian and Sankaran (1977) carried out field experiments in 1975 in summer and during kharif to study the efficiency of fluometuron. This did not perform as well as other treatments. In Bulgaria, Georgiev (1980) concluded that on the basis of trials at Sadovo between 1974 and 1979, suitable herbicides for weed control in sesame included Kotoran (fluometuron) at 1 kg/ha applied up to 2 days after sowing to control annual broadleaved weeds. The quality and fat content of sesame seeds were not adversely affected by these treatments.

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In India in Tamil Nadu, Subramanian and Sankaran (1981) conducted field experiments for 2 seasons at Coimbatore to study the effect of PRE herbicides in controlling Trianthema portulacastrum and Cyperus rotundus in sesame. Sesame was given fluometuron at 0.25-1.75 kg/ha PRE in the summer season. It did not perform as well as alachlor. In the US in South Texas, Grichar et al. (2001a) conducted field studies from 1994 through 1997 in Yoakum and in Uvalde in 1995 to evaluate soil-applied herbicides for weed control, sesame tolerance, and yield. There were four replications. The varieties used were Sesaco 11, 17, or 18. The plant height was taken from averaging 5 plants and taken 5-7 weeks after planting. The data is as follows:

Herbicide Fluometuron Rate kg/ha 0.3 1.1 Applic PRE PRE 1994 5 WAP a 43.4 16.9 Sesame height (cm) 1995 1996 7 WAP 6 WAP 120.0 47.5 127.5 51.3 131.3 43.4 31.0 11.6 1997 5 WAP 77.5 73.2 70.9 14.7

Check LSD (0.05) a WAP = weeks after planting

Fluometuron had no effect on the height. The sesame population was counted 4-6 weeks after planting. The data was as follows:

Plants/m of row Herbicide Applic Fluometuron PRE Fluometuron PRE Check LSD (0.05) a Significantly different from check Rate kg/ha 0.3 1.1 1995 66.5 70.8 70.3 23.5 1996 76.8 67.5 65.3 36.1 1997 67.5 75.0 67.5 18.8

Fluometuron had no effect on populations. The weed control is based on 0 = not control and 100 = complete control. The weed control data was as follows:

Herbicide Fluometuron Fluometuron Check LSD (0.05) Rate kg/ha 0.3 1.1 Applic PRE PRE Broadleaf signalgrass 0 21 Brown-top panicum 84 99 0 10 Southern cragrass 93 100 0 18 Palmer amaranth 1994 1995 0 25 98 100 0 4

Fluometuron was not tested in the worst year for weeds 1994, but did well in the other years. The weed control data was as follows:

Rate Herbicide kg/ha Applic Fluometuron 0.3 PRE Fluometuron 1.1 PRE Check LSD (0.05) a Significantly different from check 1994 Yoakum 650 300 1995 Yoakum 720 740 870 310 1995 Uvalde 950 1170 870 470 1996 Yoakum 500 580 480 450 1997 Yoakum 440 400 480 180

The data in the following table was converted to a percentage yield compared to the check, but the average did not include 1996 where all of the herbicides exceeded the yields of the check.

Herbicide Fluometuron Fluometuron Rate kg/ha 0.3 1.1 Applic PRE PRE 1994 Yoakum 1995 Yoakum 83 85 1995 Uvalde 109 134 1996 Yoakum 104 121 1997 Yoakum 92 83 Average 95 101

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a

Significantly different from check

Fluometuron had little effect on the sesame or the yield. In the US in Texas, Grichar and Dotray (2007) conducted PRE and POST OTT studies in two locations (Yoakum and Lubbock) in 2004 and 2005. The data from the PRE tests was as follows:

Stand reduction b Injury b Yield c Rate Weed control 2004 2005 2004 2005 2005 Treat kg/ha AMATU BRAPP Lub Yoa Yoa Lub Yoa kg/ha Check 0 0 0 0 0 0 0 380 Fluometuron 1.12 100 61 9 13 0 0 0 402 LSD (0.10) 15 28 40 25 29 29 18 217 a Bayer code for weeds: AMATU (Amaranthus tuberculatus) tall waterhemp, BRAPP (Brachiaria platyphylla) broadleaf signalgrass b Stand reduction and injury index: 0 = no stand reduction or sesame injury; 100 = complete stand reduction or plant death c Weed control and sesame yield taken at the Yoakum location only

a, c

They concluded that fluometuron shows a potential for use as a PRE herbicide for sesame. In Costa Rica, a grower guide (Anon 2007d) recommends using one PRE application of fluometuron (Cotoran 80% PM at 2 kg/ha). POST summary: No known research. In testing in 2007. Fluometuron characteristics: (Anon 1994, 1998) · Other crop uses: Has been used as a PPI, PRE, and POST. It controls many broadleaf and grass species including barnyardgrass, crabgrass, fall panicum, foxtail, goosegrass, broadleaf signalgrass, cocklebur, Florida pusley, morningglory, lambsquarters, prickly sida, common ragweed, sesbania, sicklepod, smartweed, and spurge. It can be applied in water or liquid fertilizer. · Description: White crystalline solid, odorless. · Symptomology: Injury begins as interveinal chlorosis of the leaves, followed in susceptible plants by increased chlorosis and necrosis. Cotyledons may show chlorotic areas. Older leaves show more damage than new growth. Root growth is not affected. · Absorption/translocation: Readily absorbed by roots after soil application and translocated via the apoplast (including xylem) to the shoots. Foliar-applied it is not highly absorbed and is not appreciably translocated out of the treated leaf via the phloem. · Mechanism of action: Inhibits photosynthesis. Death occurs from oxidation of proteins and lipids. · Sorption: Moderately adsorbed to soil. · Transformation: - Photodegradation: losses are substantial when little or no rainfall is received soon after application, but are moderate to low with adequate rainfall. - Other degradation: Half-life was 189 days from aerobic microbial metabolism and 376 days for anaerobic microbial metabolism. · Persistence: Average field half-life is 85 days. Residues often dissipate to non-detectable levels by 4 months after application of labeled rates. · Mobility: No quantifiable residues were found below 30 cm (12 inches). · Volatilization: Negligible losses. · Miscellaneous information:

Common name Fluometuron Trade name Cotoran Date 1974 Avg rate (lbs/ac) 2.4 LD50 rat (mg/kg) 1,840

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Current sample of label: http://www.fluorideaction.org/pesticides/msds/fluometuron.label.cotoran.4l.pdf

Using the sample label above for Cotoran 4L, there are rotational restrictions from immediate to 12 months depending on the crop and the amount of the herbicide used. For most crops, they can be planted 6 months after the last application. Refer to the current label for current restrictions.

FLUORODIFEN (Preforan)

Out of production in US PRE summary: Toxic to sesame with substantial damage to sesame seedlings. In Ethiopia, Moore (1973a, 1974) evaluated herbicides for use in sesame grown on a dark brown sandy clay loam under irrigation at Melka Werer. The performance of fluorodifen (2.2 kg and 3kg/ha) PRE was unsatisfactory due possibly to heavy irrigation which followed the application. In Ethiopia, Moore (1973b, 1974) carried out a trial in the higher rainfall area at Setit Humera where irrigation was not necessary. Fluorodifen PRE caused substantial damage to sesame seedlings. In Egypt, Hussien et al. (1983) studied fluorodifen PRE. Two checks were used ­ one hand-hoed and the other with weeds. Fluorodifen was good on annual broadleaves. Fluoradifen at 3.24 kg/ha was among the most harmful treatments; however, it produced at yield increase of 44% over the unweeded check. Increase in seed yield by hand-hoeing was about 30% compared to the unweeded check. Seed oil content of sesame was not affected by the weed control treatments. POST summary: No known research.

FOMESAFEN (Flex, Reflex)

PRE summary: No known research. POST OTT summary: Mixed results in that it is toxic to sesame in reducing yield, but in one test in weedy conditions can improve yield over weedy check. Too risky to use. In the US in South Texas, Grichar and Langham (2003) conducted a POST OTT test. A 5 ft swath of herbicides was sprayed across three rows of five lines leaving 15 ft of each row untouched to allow a direct within row comparison of the effects of the treatments. The herbicides were sprayed over the top in the juvenile stage when the plants were about 18" tall. There was a dual purpose: (1) find herbicides that were selective to sesame and (2) find herbicides that would control volunteer sesame in other crops. In this test, there were no weeds since the main thrust of the study was to look at the effects of the herbicide on the sesame. There were no replications in that the idea was to take the better lines and test them in Grichar et al. (2007). At the end of the ripening phase, the plots were evaluated in terms of percentage production compared to the untouched plants in the same row.

Treatment Fomesafen Rate 0.5x 1.0x Average S26 30 40 37 S27 40 70 49 S28 30 50 37 S29 40 50 48 132 40 40 31 Average 36 50 40

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This is one of the few treatments where the high rate had higher production. However, there was still too much damage to the sesame. In the US, Grichar and Dotray (2007) conducted POST OTT studies in two locations in Texas (Yoakum and Lubbock) in 2004 and 2005. The herbicides were applied in the pre-reproductive stage when the plants were about 60 cm tall. The Lubbock trials were virtually weed free while there were weeds in the Yoakum trials. The data from the tests was as follows:

Sesame injury (%) a Yield (kg/ha) Rate 2004 2005 2004 2005 Treatment b kg/ha Lub Yoa Lub Yoa Lub Lub Yoa Check 0 0 0 0 125 1,008 314 Fomesafen 0.21 55 53 15 13 28 896 621 LSD (0.10) 11 36 20 105 226 a Injury index: 0 = no sesame injury; 100 = complete plant death. Ratings taken 6-8 wks after herbicide application b All herbicides included a non-ionic surfactant added at 0.25% v/v or a crop oil concentrate added at 1 qt/ac.

Their conclusions were as follows: · In Lubbock where there were no weeds, the treatment reduced the yield, while in Yoakum, the treatment by controlling the weeds had a higher yield than the control. · The treatment caused intermediate injury to the sesame in Lubbock with less injury in Yoakum. In Argentina in Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3 replications. There were 3 rains before emergence. The POST OTT herbicides were applied 19 days after planting. The weed control data was taken 13 days after application and was as follows:

Herbicide Flex Ama a Rha a 85 80 55 90 Weed-free check 100 100 Weedy check 0 0 Weed control with 0 = no control and 100 = complete control. Ama = Amaranthus quitensis and Rha = Raphanus sativus Active ingredient Fomesafen Rate/ha 350 cc 700 cc

a

There were three ratings done 13, 43, and 70 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight from capsules in the center of the capsule zone. The number of seeds were counted and the seed weight per capsule (SWC) and was taken. The POST OTT data was as follows:

13 43 DDAa DDA Fomesafen low rate 30 18 Fomesafen high rate 8 5 Weed-free check 81 83 Weedy check 75 71 a DDA = days after application Active ingredient 70 DDA 30 8 78 65 Yieldg (g/m) W100 (g) Sd/cap SWC (g)

48.4 ab 50.7 ab

0.300 0.300

74.1 62.8

0.222 0.188

The fomesafen did not have good weed control and it substantially reduced the stand of sesame. POST DIR summary: No known research.

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FORAMSULFURON + IODOSULFURON (Equip)

PRE summary: No known research. POST OTT summary: Toxic to sesame with almost complete kill. In Argentina in Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3 replications. There were 3 rains before emergence. The POST OTT herbicides were applied 19 days after planting. The weed control data was taken 13 days after application and was as follows:

Herbicide Equip Active ingredient Rate/ha Ama a Foramsulfuron + 120g 100 Iodosulfuron Weed-free check 100 Weedy check 0 Weed control with 0 = no control and 100 = complete control. Rha = Raphanus sativus Rha a 100 100 0 Ama = Amaranthus quitensis and

a

There were three ratings done 13, 43, and 70 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight from capsules in the center of the capsule zone. The number of seeds were counted and the seed weight per capsule (SWC) and was taken. The POST OTT data was as follows:

Active ingredient 13 DDAa 43 DDA 0 83 71 70 DDA 2 78 65 Yieldg (g/m) W100 (g) Sd/cap SWC (g) Foramsulfuron + 0 Iodosulfuron Weed-free check 81 Weedy check 75 a DDA = days after application

48.4 ab 50.7 ab

0.300 0.300

74.1 62.8

0.222 0.188

Equip had complete weed and sesame control. POST DIR summary: No known research.

GLUFOSINATE (Liberty, Finale, Rely, Ignite, Basta)

Sesame use: Potential use as POST DIR and/or a harvest aid. PRE summary: No known research. POST OTT summary: No known research. POST DIR summary: There is burning of the sesame leaves that come in contact with the herbicide, but the plants recover and there is minimum yield reduction. Needs more research before using in farmer fields. Only drawback is that it does not provide residual control. In further testing in 2007.

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Grichar, Dotray, and Langham experimented with POST DIR treatments in Uvalde and Lubbock in 2006. The experiment is being repeated in 2007. The herbicides were applied 2" and 6" from the ground on both sides of the stem when the plants were about 18" tall in the juvenile stage. The treatments were replicated 3 times. In Uvalde the experiment was under a lateral pivot with extreme variation. As a result the yield data was taken by cutting a sample within the treatment and a sample in the adjacent untreated row. The yield below is a percent of the treated row divided by the untreated row. The Lubbock experiment was rainfed with some variation between rows, and the percentage yield below represents the treatment plot divided by the check plot. In both locations the day after planting, a PRE treatment of metolachlor plus glyphosate was sprayed over the fields. There was no weed pressure in either location since the purpose of the initial experiment was to find herbicides that would be selective to sesame.

Active ingredient Glufosinate Rate lbs/ ac 0.52 Height of applic 2" 6" Stunting Lub 3 6 Uva Yield % of check Lub Uva 91 108 88 108

This treatment shows some potential with minor reductions in yield. There is an immediate burning of the leaves that come in contact with the herbicide, but the plants recover and there is little yield loss. Harvest aid summary: Potential use as a harvest aid. Needs much more research before farmer use. Glufosinate characteristics: (Anon 1994, 1998) · Other crop uses: Used POST and POST DIR. It is non selective and controls a wide spectrum of annual and perennial grass and broadleaf weeds. · Description: White to light-yellow crystalline powder, slightly pungent odor. · Symptomology: Chlorosis and wilting usually occur 3-5 days after application, followed by necrosis in 1-2 weeks. Tate of symptom increased by bright sunlight, high humidity, and moist soil. Seedlings are not injured before emergence. · Absorption/translocation: Requires a 6 hour rain free period after application for maximum efficacy. Little to no absorption through the roots under field conditions because of rapid microbial breakdown. Movement in xylem or phloem is limited. · Mechanism of action: Inhibits action of essential enzymes. · Sorption: Weakly adsorbed to the soil · Transformation: - Photodegradation: Not available. - Other degradation: Readily degraded by microbes in sil and surface water. · Persistence: Short soil residual life with typical field half-life of 7 days. · Mobility: Highly mobile in soil. Despite high leaching potential, glufosinate has been detected no deeper than 15 cm, presumably because of rapid microbial degradation. · Volatilization: Not available. · Miscellaneous information:

Common name Trade name Date Avg rate (lbs/ac) LD50 rat (mg/kg) Glufosinate Liberty/Finale/Rely 1993 0.65 1,910 Current sample of label: http://www.bayercropscienceus.com/content/MSDSLabel/MSDSLabel635-1688264829%20Ignite%20280%20SL%20Label%20revised%207-18-05.pdf

Using the sample label above for Ignite, there are rotational restrictions from immediate to 120 days after last application. Corn, cotton, and soybeans may be planted immediately, while wheat, rye, and sorghum may be planted 70 days later. Refer to the current label for current restrictions.

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GLYPHOSATE (Roundup, RT3, Touchdown, Buccaneer, Durango)

Sesame use: Used in commercial PREPLANT or PRE as a burndown for existing weeds. US label for RT3. RT3 can be applied before, during, or after planting. Broadcast must be done before the crop emerges. Wiper applicators or hooded sprayers can be used between the rows after the crop has been established. Potential to be used as a harvest aid. PRE summary: No known research to verify there is no damage; however, no differences have been seen in areas that have not been sprayed or double sprayed next to an area that has been sprayed. In the US, the first author has made the following observations: · Glyphosate has been used PREPLANT extensively to kill off the weeds. Within the nurseries, glyphosate has been added PRE along with the metolachlor after planting to kill weeds that have not been killed by the harrowing. There has never been a stand of sesame lost because of glyphosate. However, there are soils that crack and in high temperatures sesame germinates quickly. Glyphosate should not be applied more than 2 days after planting even if sesame is not above the ground because there is a chance that the seedling is exposed from cracks in the seed bed. · In one known case where the glyphosate was applied 3 days after planting, there was little emergence in the area planted first and then there was less population and by mid field, there was a good stand. POST OTT summary: Toxic to sesame. Will kill the sesame and drift from adjacent field applications can stunt the sesame severely. In the US in South Texas, Grichar and Langham (2003) conducted a POST OTT test. A 5 ft swath of herbicides was sprayed across three rows of five lines leaving 15 ft of each row untouched to allow a direct within row comparison of the effects of the treatments. The herbicides were sprayed over the top in the juvenile stage when the plants were about 18" tall. There was a dual purpose: (1) find herbicides that were selective to sesame and (2) find herbicides that would control volunteer sesame in other crops. In this test, there were no weeds since the main thrust of the study was to look at the effects of the herbicide on the sesame. There were no replications in that the idea was to take the better lines and test them in Grichar et al. (2007). At the end of the ripening phase, the plots were evaluated in terms of percentage production compared to the untouched plants in the same row.

Treatment Glyphosate Rate 0.5x 1.0x Average S26 5 5 37 S27 10 10 49 S28 20 5 37 S29 20 5 48 132 5 5 31 Average 12 6 40

Within 2 weeks of the spraying all of the plants with contact from the glyphosate were dead. The dominant plants covered the minor plants and reduced the amount of the chemical that came in contact, and those minor plants are the ones that are rated above. In the US, the first author has made the following observations: · When glyphosate is used along the edges of the field for border weed control, there is injury to the sesame but usually it is not killed.

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· In one case where glyphosate was flown on to an adjacent field, there was drift which killed the sesame near the other field and then a gradual severe to moderate to no injury into about 30 meters of the sesame field. · After planting sesame, with the use of Roundup Ready cotton, there are no problems with sesame as a weed in cotton as there was in previous years. · Within sesame, farmers have successful used glyphosate with a wick and controlled the weeds without damage to the sesame. The one exception was when there was a leak in the wick and there was a row of severely stunted sesame the same distance from the tires of the tractor throughout one field. POST DIR summary: Directed in the center between the rows has not had problems. Spraying on the stem depends on the height of the plant and the height of the application on the plant. In some cases there has been no effect and in other cases the glyphosate has been toxic. More research needs to be done to determine the safe rates, height on the stem, and stages of growth. In further testing in 2007 by itself and in combination with diuron, flumioxazin, and prometryn. In the US in Texas, Grichar, Dotray, and Langham experimented with POST DIR treatments in Uvalde and Lubbock in 2006. The experiment is being repeated in 2007. The herbicides were applied 2" and 6" from the ground on both sides of the stem when the plants were about 18" tall in the juvenile stage. The treatments were replicated 3 times. In Uvalde the experiment was under a lateral pivot with extreme variation. As a result the yield data was taken by cutting a sample within the treatment and a sample in the adjacent untreated row. The yield below is a percent of the treated row divided by the untreated row. The Lubbock experiment was rainfed with some variation between rows, and the percentage yield below represents the treatment plot divided by the check plot. In both locations the day after planting, a PRE treatment of metolachlor plus glyphosate was sprayed over the fields. There was no weed pressure in either location since the purpose of the initial experiment was to find herbicides that would be selective to sesame.

Active ingredient Prometryn + Glyphosate Diuron + Glyphosate Glyphosate Flumioxazin + Glyphosate Rate lbs/ ac 1.0 0.75 0.75 0.75 0.75 0.063 0.75 Height of applic 2" 6" 2" 6" 2" 6" 2" 6" Stunting Lub 0 3 0 5 13 30 0 5 Uva Yield % of check Lub Uva 75 110 65 85 62 90 46 84 86 130 44 116 56 108 64 108

The glyphosate was applied by itself and in combination with other herbicides. In Uvalde, the glyphosate helped on the yield in most cases. In this field there was a high population with dominant and minor plants. The minor plants were the plants that were killed by the glyphosate. This reduced the population which was beneficial since minor plants are in effect a weed in that they use moisture and fertility without a commensurate contribution to the yield. In Lubbock, the glyphosate reduced the yield. In the US, the first author has made the following observations: · Hooded sprayers with the side nozzles turned off have controlled weeds in the furrow without damaging the sesame.

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· In the Lubbock nursery in 2005, the farmer was using glyphosate on cotton and POST DIR sprayed a strip with morningglory with the chemicals hitting the stems of the sesame about 3" from the ground when the sesame was 18" tall. There was no visible damage to the sesame. The existing morningglory plants were killed, but there was a flush of new morningglory later. However, the rate is critical since when the tractor stopped and did not turn off the spray immediately, all of the plants in 8 rows for 4 ft died. Harvest aid summary: Good potential to be used as a harvest aid. Needs much more research before farmer use. Glyphosate characteristics: (Anon 1994, 1998) · Other crop uses: Has been used PREPLANT, PRE, POST, and POST DIR. It controls virtually all annual and perennial weeds, but generally is most phytotoxic to annual grasses. A non-ionic surfactant is required for maximum efficacy, although certain formulated products already contain surfactants. · Description: Acid - white color, odorless. TMS salt ­ clear amber to yellow liquid and slight sulfur odor. · Symptomology: Growth is inhibited soon after application followed by general foliar chlorosis within 4-7 days for highly susceptible grasses and within 10-20 days for less susceptible species. Chlorosis may appear first and be most pronounced in immature leaves and growing points. · Absorption/translocation: Moderately absorbed across the cuticle when POST applied. Primarily translocated in the symplast with accumulation in underground tissues, immature leaves, and meristems. · Mechanism of action: Inhibits essential enzymes that are needed for synthesizing proteins. · Sorption: Rapidly and tightly adsorbed to soil. OM, clay, silt, or sand content and soil pH have minimal effect on adsorption. Strong adsorption to soils is evidenced in part by low phytotoxicity with soil applications. Crops can be seeded or transplanted immediately into treated areas. · Transformation: - Photodegradation: Negligible losses. - Other degradation: Degraded microbially in soil and water. · Persistence: Has moderate persistence with a typical field half-life of 47 days. All crops can be planted immediately after application due to strong adsorption to the soil. · Mobility: Low mobility in moist soils and low potential for movement and runoff. · Volatilization: Negligible losses. · Miscellaneous information:

Common name Trade name Date Avg rate (lbs/ac) LD50 rat (mg/kg) Glyphosate Roundup 1971 0.65 5,400 Current sample of label: http://www.monsanto.com/monsanto/ag_products/pdf/labels_msds/rt_3_label.pdf

Using the sample label above for RT3, there are rotational restrictions from immediate to 30 days depending on the crop and the amount of the herbicide used. The following are the restrictions for the common crops in the sesame growing areas in the US as of 24 July 07, but refer to the current label for current restrictions. Corn, cotton, rye, sorghum, soybean, and wheat may be planted immediately. Alfalfa and peanuts are not on the label and thus there is a 30 day waiting period between last application and planting.

HALOXYFOP (Verdict)

Sesame use: Used in commercial fields as a POST. No US label.

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PRE summary: No known research. POST OTT summary: No known research, but researchers report using it without a problem. In Australia in South Burnett, a grower guide (Sapin et al. 2000) states that sesame is susceptible to, but will tolerate haloxyfop (Verdict), but it is not registered in Australia. In Australia in the Northern Territories, M. Bennett (2003, 2007, pers. commun.): "We have no approved herbicides for sesame and need `minor crop' usage approval from the relevant authority. If grass weeds become a problem post emerge we use Verdict (haloxyfop) at recommended rates." In Australia, Jim Barnes (2007, pers. commun.) stated: "My observations were that just about any post emergence grass killing herbicides were OK (we did not try them all but haloxyfop was OK) although I have heard about others being used. Most of these herbicides are only active against grasses anyway so should be OK." POST DIR summary: No known research, but logically if the grass weeds are short, a POST DIR application would allow contact with the small weeds in the seed line which are protected by the sesame plants from an over the top application.

IMAZAMOX (Beyond)

PRE summary: No known research. No experience with using this product in wheat prior to planting sesame. However, Beyond label specifies 9-26 month rotation for broadleaves that are not Cleafield®. POST summary: No known research.

IMAZAPIC (Cadre)

PRE summary: No known research, but in carry over from a peanut application there was close to zero germination. In the US, the first author has made the following observations: · Sesame has followed peanuts that had imazapic with good stands. In one year there was a nursery planted next to peanuts and six rows had virtually no stand. In talking to the person that had applied the imazapic to the peanuts he admitted that part of the boom went over 6 rows of intended sesame nursery. There were a few lines of sesame that had perfect stands in the 10 meters they were planted, but this apparent tolerance has not been followed up because of the 18 month plant-back restrictions. Sesame is primarily a rotation crop, and the fields need to be rotated back to the primary crop. · Thinking that because there was some resistance in some lines from a PREPLANT application of imazapic, imazapic was applied POST OTT over 27 lines that included the resistant lines plus lines that were progeny from the resistant lines. Imazapic was toxic to all the lines, but did not kill any of the sesame.

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POST OTT summary: Toxic to sesame with stunting and substantial yield reduction. In the US in South Texas, Grichar et al. (2001b) conducted POST OTT studies in weed free areas at Yoakum and Uvalde from 1994 to 1997. The varieties used were Sesaco 11, 17, or 18. The herbicides were applied over the top 3-4 wk after planting in Yoakum and 6 wk after planting in Uvalde. Sesame was 30-48 cm in height at the time of application. Planting dates in Yoakum were 26 May 1994, 11 July 1995, 12 July 1996, and 1 July 1997. Planting date in Uvalde was 28 April 1995. In 1995 none of the herbicides reduced stands while in 1997, high rate of imazapic reduced the stands by 73%. Ratings of stunting (0= no stunting and 100 = total stunting) were done 3 weeks after herbicide application as shown below.

Rate (kg/ha) Check Imazapic LSD (0.05) Rate (kg/ha) Check Imazapic LSD (0.05) Rate (kg/ha) Check Imazapic LSD (0.05) 0.04 0.07 0.04 0.07 0.04 0.07 94 YOA 0 83 87 28 94 YOA 91 0 0 26 94 YOA 408 0 0 248 95 UVA 0 50 70 19 95 YOA 110 35 68 32 95 UVA 844 260 107 210 95 YOA 0 84 88 12 96 YOA 71 27 23 23 95 YOA 482 363 344 255 96 YOA 0 67 87 22 97 YOA 74 25 17 16 96 YOA 419 46 81 217 97 YOA 501 582 564 NS Avg 531 250 219 % check 47 41 97 YOA 0 86 94 12

Imazapic stunted the sesame severely. The effects on plant height (cm) were as follows:

Imazapic reduced the heights substantially. The yields (kg/ha) were as follows:

Imazapic reduced the yields substantially. In the US in South Texas, Grichar and Langham (2003) conducted a POST OTT test. A 5 ft swath of herbicides was sprayed across three rows of five lines leaving 15 ft of each row untouched to allow a direct within row comparison of the effects of the treatments. The herbicides were sprayed over the top in the juvenile stage when the plants were about 18" tall. There was a dual purpose: (1) find herbicides that were selective to sesame and (2) find herbicides that would control volunteer sesame in other crops. In this test, there were no weeds since the main thrust of the study was to look at the effects of the herbicide on the sesame. There were no replications in that the idea was to take the better lines and test them in Grichar et al. (2007). At the end of the ripening phase, the plots were evaluated in terms of percentage production compared to the untouched plants in the same row.

Treatment Imazapic Rate 0.5x 1.0x Average S26 60 70 37 S27 60 70 49 S28 60 50 37 S29 80 50 48 132 40 50 31 Average 60 58 40

Imazapic was one of the best treatments in terms of lower production loss than the other treatments at the end, but initially there was severe stunting. In Argentina in Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3

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replications. There were 3 rains before emergence. The POST OTT herbicides were applied 19 days after planting. The weed control data was taken 13 days after application and was as follows:

Herbicide Cadre Active ingredient Rate/ha Ama a Rha a Imazapic 72 g 100 100 Weed-free check 100 100 Weedy check 0 0 Weed control with 0 = no control and 100 = complete control. Ama = Amaranthus quitensis and Rha = Raphanus sativus

a

There were three ratings done 13, 43, and 70 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight from capsules in the center of the capsule zone. The number of seeds were counted and the seed weight per capsule (SWC) and was taken. The POST OTT data was as follows:

13 43 DDAa DDA Imazapic 5 0 Weed-free check 81 83 Weedy check 75 71 a DDA = days after application Active ingredient 70 DDA 0 78 65 Yieldg (g/m) 48.4 ab 50.7 ab W100 (g) 0.300 0.300 Sd/cap SWC (g) 0.222 0.188

74.1 62.8

The imazapic had great weed control, but also destroyed the sesame. In the US, the first author has made the following observations: · Thinking that because there was some resistance in some lines from a PREPLANT application of imazapic, imazapic was applied POST OTT over 27 lines that included the resistant lines plus lines that were progeny from the resistant lines. Imazapic was toxic to all the lines, but did not kill any of the sesame. POST DIR summary: No known research. Not included in testing because of rotational restrictions.

IMAZETHAPYR (Pursuit)

PRE summary: Somewhat selective in that it reduces stand and plant height, but at a low rate it increased yield over a weedy check. In the US in South Texas, Grichar et al. (2001a) conducted field studies from 1994 through 1997 in Yoakum and in Uvalde in 1995 to evaluate soil-applied herbicides for weed control, sesame tolerance, and yield. There were four replications. The varieties used were Sesaco 11, 17, or 18. The plant height was taken from averaging 5 plants and taken 5-7 weeks after planting. The data is as follows:

Herbicide Imazethapyr Rate kg/ha 0.04 0.07 Applic PRE PRE 1994 5 WAP a 11.6 b 7.1 b 43.4 16.9 Sesame height (cm) 1995 1996 7 WAP 6 WAP 117.9 40.4 120.9 38.9 131.3 43.4 31.0 11.6 1997 5 WAP 75.7 70.6 70.9 14.7

Check LSD (0.05) a WAP = weeks after planting

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Significantly different from check

Imazethapyr only reduced the height in 1994. The sesame population was counted 4-6 weeks after planting. The data was as follows:

Plants/m of row Herbicide Imazethapyr Rate kg/ha 0.04 0.07 Applic PRE PRE 1995 54.5 63.0 70.3 23.5 1996 18.0 a 43.5 65.3 36.1 1997 47.4 a 62.4 67.5 18.8

Check LSD (0.05) a Significantly different from check

Imazethapyr lowered the population in all trials and significantly in two, but in the latter two it was not at the high rate. Why would a lower rate have more of an effect? The weed control is based on 0 = not control and 100 = complete control. The weed control data was as follows:

Herbicide Imazethapyr Check LSD (0.05) Rate kg/ha 0.04 0.07 Applic PRE PRE Broadleaf signalgrass 80 87 0 21 Brown-top panicum 94 90 0 10 Southern cragrass 86 88 0 18 Palmer amaranth 1994 1995 95 100 0 25 95 99 0 4

Imazethapyr along with metolachlor provided the most consistent weed control (>80%). The weed control data was as follows:

Herbicide Imazethapyr Rate kg/ha 0.04 0.07 Applic PRE PRE 1994 Yoakum 460 340 a 650 300 1995 Yoakum 810 630 870 310 1995 Uvalde 1490 a 860 870 470 1996 Yoakum 720 590 480 450 1997 Yoakum 470 480 480 180

Check LSD (0.05) a Significantly different from check

The data in the following table was converted to a percentage yield compared to the check, but the average did not include 1996 where all of the herbicides exceeded the yields of the check.

Herbicide Imazethapyr Rate 1994 kg/ha Applic Yoakum 0.04 PRE 71 0.07 PRE 52 a a Significantly different from check 1995 Yoakum 93 72 1995 Uvalde 171 a 99 1996 Yoakum 150 123 1997 Yoakum 98 100 Average 108 81

Imazethapyr was near the check at the low rate, but reduced yield at the high rate. Although imazethapyr provided good weed control, it affected the yield more than would be indicated by effects on plant height and population. POST OTT summary: Toxic to sesame with substantial stunting and yield reduction; however, in one test, outyielded the weedy check. Too risky to use. In the US in South Texas, Grichar et al. (2001b) conducted POST OTT studies in weed free areas at Yoakum and Uvalde from 1994 to 1997. The varieties used were Sesaco 11, 17, or 18. The herbicides were applied over the top 3-4 wk after planting in Yoakum and 6 wk after planting in Uvalde. Sesame was 30-48 cm in height at the time of application. Planting dates in Yoakum were 26 May 1994, 11 July 1995, 12 July 1996, and 1 July 1997. Planting date in Uvalde was 28 April 1995. Ratings of stunting (0= no stunting and 100 = total stunting) were done 3 weeks after herbicide application as shown below.

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Rate (kg/ha) Check Imazethapyr LSD (0.05) Rate (kg/ha) Check Imazethapyr LSD (0.05) Rate (kg/ha) Check Imazethapyr LSD (0.05) 0.04 0.07 0.04 0.07 0.04 0.07

94 YOA 0 42 63 28 94 YOA 91 61 34 26 94 YOA 408 267 282 248

95 UVA 0 13 19 19 95 YOA 110 78 49 32 95 UVA 844 413 390 210

95 YOA 0 64 76 12 96 YOA 71 30 18 23 95 YOA 482 608 484 255

96 YOA 0 65 75 22 97 YOA 74 45 36 16 96 YOA 419 897 18 217

97 YOA 0 63 72 12

Imazethapyr showed severe stunting. The effects on plant height (cm) were as follows:

Imazethapyr reduced the plant heights substantially. The yields (kg/ha) were as follows:

97 YOA 501 548 470 NS Avg 531 547 329 % check 103 62

The imazethapyr averaged the same yield as the check primarily because in Yoakum with a lot of weeds, the weed control was good and helped the yield. In Uvalde in 1995 with little weed pressure, imazethapyr reduced the yields by over 50%. In the US in South Texas, Grichar and Langham (2003) conducted a POST OTT test. A 5 ft swath of herbicides was sprayed across three rows of five lines leaving 15 ft of each row untouched to allow a direct within row comparison of the effects of the treatments. The herbicides were sprayed over the top in the juvenile stage when the plants were about 18" tall. There was a dual purpose: (1) find herbicides that were selective to sesame and (2) find herbicides that would control volunteer sesame in other crops. In this test, there were no weeds since the main thrust of the study was to look at the effects of the herbicide on the sesame. There were no replications in that the idea was to take the better lines and test them in Grichar et al. (2007). At the end of the ripening phase, the plots were evaluated in terms of percentage production compared to the untouched plants in the same row.

Treatment Imazethapyr Rate 0.5x 1.0x Average S26 40 40 37 S27 70 50 49 S28 40 40 37 S29 50 50 48 132 30 20 31 Average 46 40 40

Imazethapyr had severe production reduction. POST DIR summary: No known research. Not included in testing because of rotational restrictions.

ISOPROPALIN (Parlaan, EL-179)

PRE summary: Toxic to sesame with reductions in stand and medium injury. In the US in California, St Andre (1969) conducted PPI trials under furrow irrigation, planted 10 Jun. Variety was Baco planted at 2.5 lbs/ac. The stand counts were done 5 Jun and the ratings 10 Jun.

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Visual rating b Herbicide Rate Barley Sesame lb/ac control injury EL-179 (isopropalin) 1.0 38.0 11.3 2.3 4.3 2.0 37.0 12.6 5.0 4.6 Untreated --55.3 21.6 0 0 a Stand count values represent the average number of plants in 8 feet of row b Ratings based on 0-10 scale. 0 = no control or injury. 10 = perfect control or very severe injury. Injury rating reflects retardation and vigor in the growth of sesame.

Stand count a Sesame Barley

Isopropalin was not one of the best treatments in terms or either little sesame injury or good weed control. In the US in California, Fischer (1971) summarized the work that had been done between 1967 and 1970 in the San Joaquin valley to include the results of St Andre (1969, 1970a, and 1970b). In that area the concept was to grow sesame double cropped after barley or other cereals, and thus the emphasis was on controlling volunteer grasses. He summarized the results for the years as follows:

Trade name EL-179 Active ingredient Isopropalin Lbs/ac evaluated 1.0/2.0 Sesame tolerance Poor Barley control Erratic

POST summary: No known research.

LACTOFEN (Cobra)

PRE summary: No known research. POST OTT summary: Toxic to sesame with substantial yield reduction, but did not kill the sesame. In the US, Grichar and Dotray (2007) conducted POST OTT studies in two locations in Texas (Yoakum and Lubbock) in 2004 and 2005. The herbicides were applied in the pre-reproductive stage when the plants were about 60 cm tall. The Lubbock trials were virtually weed free while there were weeds in the Yoakum trials. The data from the tests was as follows:

Sesame injury (%) a Yield (kg/ha) Rate 2004 2005 2004 2005 Treatment b kg/ha Lub Yoa Lub Yoa Lub Lub Yoa Check 0 0 0 0 125 1,008 314 Lactofen 0.20 99 57 38 25 0 698 320 LSD (0.10) 11 36 20 105 226 a Injury index: 0 = no sesame injury; 100 = complete plant death. Ratings taken 6-8 wks after herbicide application b All herbicides included a non-ionic surfactant added at 0.25% v/v or a crop oil concentrate added at 1 qt/ac.

Their conclusions were as follows: · In Lubbock where there were no weeds, the treatment reduced the yield substantially, while in Yoakum, this was one of the few treatments that did not have a higher yield than the control. · The treatment caused severe injury to the sesame in Lubbock and intermediate injury in Yoakum.

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In the US in South Texas, Grichar and Langham (2003) conducted a POST OTT test. A 5 ft swath of herbicides was sprayed across three rows of five lines leaving 15 ft of each row untouched to allow a direct within row comparison of the effects of the treatments. The herbicides were sprayed over the top in the juvenile stage when the plants were about 18" tall. There was a dual purpose: (1) find herbicides that were selective to sesame and (2) find herbicides that would control volunteer sesame in other crops. In this test, there were no weeds since the main thrust of the study was to look at the effects of the herbicide on the sesame. There were no replications in that the idea was to take the better lines and test them in Grichar et al. (2007). At the end of the ripening phase, the plots were evaluated in terms of percentage production compared to the untouched line in the same row.

Treatment Lactofen Rate 0.5x 1.0x Average S26 50 40 37 S27 60 50 49 S28 50 50 37 S29 50 50 48 132 40 30 31 Average 50 44 40

Lactofen reduced the production substantially even though it was one of the better treatments. In Argentina in Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3 replications. There were 3 rains before emergence. The POST OTT herbicides were applied 19 days after planting. The weed control data was taken 13 days after application and was as follows:

Herbicide Cobra Active ingredient Rate/ha Ama a Lactofen 300 cc 100 Weed-free check 100 Weedy check 0 Weed control with 0 = no control and 100 = complete control. Rha = Raphanus sativus Rha a 100 100 0 Ama = Amaranthus quitensis and

a

There were three ratings done 13, 43, and 70 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight from capsules in the center of the capsule zone. The number of seeds were counted and the seed weight per capsule (SWC) and was taken. The POST OTT data was as follows:

13 43 DDAa DDA Lactofen 5 12 Weed-free check 81 83 Weedy check 75 71 a DDA = days after application Active ingredient 70 DDA 17 78 65 Yieldg (g/m) 48.4 ab 50.7 ab W100 (g) 0.300 0.300 Sd/cap SWC (g) 0.222 0.188

74.1 62.8

The lactofen had severe injury leaving little stand at the end. POST DIR summary: Some reduction in yield. Dark marks on stem at level of application. In further testing in 2007. In the US in Texas, Grichar, Dotray, and Langham experimented with POST DIR treatments in Uvalde and Lubbock in 2006. The experiment is being repeated in 2007. The herbicides were applied 2" and 6" from the ground on both sides of the stem when the plants were about 18" tall in the juvenile stage. The treatments were replicated 3 times. In Uvalde the experiment was under a lateral pivot with extreme variation. As a result the yield data was taken by cutting a sample within the treatment and a sample in the adjacent untreated row. The yield below is a percent of the treated row divided by the untreated row. The Lubbock experiment was rainfed

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with some variation between rows, and the percentage yield below represents the treatment plot divided by the check plot. In both locations the day after planting, a PRE treatment of metolachlor plus glyphosate was sprayed over the fields. There was no weed pressure in either location since the purpose of the initial experiment was to find herbicides that would be selective to sesame.

Active ingredient Lactofen Rate lbs/ ac 0.2 Height of applic 2" 6" Stunting Lub 0 5 Uva Yield % of check Lub Uva 81 87 74 79

In examining the plants after the spraying, there is a dark line that looks like a bruise where the herbicide struck the sesame. There is no line on the side protected form the spray. In low populations where a plant was struck on both sides, the plants broke over at that point.

LINURON (Lorox, Afalon, Linex, Linurex.

Layby Pro mixes linuron and diuron)

Sesame use: Used in commercial fields as PRE. Good potential as POST DIR combined with diuron in Layby Pro. No label in US. PRE summary: Selective to sesame and good weed control. In further testing in 2007. In the US, Culp and McWhorter (1965) cited Santelmann et al. (1963) who found slight phytotoxicity and yield reduction occurred with linuron at low rates, but linuron at 2 lbs/ac reduced yields. In Venezuela, Montilla (1964) had an experiment with Lorox (linuron). The herbicide was applied PRE. Treatment Dose/ha Broad cont Grass cont Sesame germ Lorox 1 kg 67 40 Good The Lorox did not have as good weed control as the other herbicides in the experiment. In Bulgaria, Lyubenov and Kostadinov (1970) conducted trials in 1969 with sesame sown on chernozem smolnitsa soil on 29 May. PRE application of mixtures of 3 kg/ha Afalon (linuron) with 3 kg/ha Lasso (alachlor) or 5 kg/ha Ramrod (propachlor) gave effective control of weeds and increased seed yields and seed oil content. In Egypt, Hussien et al. (1983) studied linuron PRE. Two checks were used ­ one hand-hoed and the other with weeds. Linuron was good on annual broadleaves. Linuron at 1.8 kg/ha provided significant increase in seed yield/ha by 60 as compared to the unweeded check. Increase in seed yield by hand-hoeing was about 30% compared to the unweeded check. Seed oil content of sesame was not affected by the weed control treatments. In Australia in Queensland, Schrodter and Rawson (1984) evaluated PRE herbicides on sesame grown under weed free and weedy conditions in Lockyer Valley in 3 experiments over two years. The following were the results of the first two experiments:

Herbicide Linuron (PRE) Rate kg/ha 1.1 2.2 Number of plants a 62 a Yield kg/ha 144 bd Number of plants 293 ab 278 ab Yield kg/ha 414 ab 425 ab Plant height cm d 19 ab 16 c

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Herbicide

Rate kg/ha

Weed free control Weedy control a 1000s/ha b Means not followed by a common letter differ significantly (P<0.05) c Experiment says PRE but probably PPI d Measured 29 days after planting

Number of plants a 59 a 52 ac

Yield kg/ha 431 a 55d

Number of plants 251 b 322 a

Yield kg/ha 385 b 431 ab

Plant height cm d 18 abc 20 a

The results of experiment 1 were as follows: · Linuron had no significant effect on the populations · Yield in the weedy control was reduced 87% when compared to the weed free control. The weed free control significantly outyielded all the treatments except for the high rate of alachlor. The results of experiment 2 were as follows: · Linuron had no effect on the crop. · The reduction of population in the weed free control was probably a loss during the hand weeding operation. In experiment 3, the successful treatments were repeated and a few new herbicides were tried as follows:

Herbicide Linuron Bentazon (POST) e Rate kg/ha 2.25 0.96 Type of plot Weedy Weed free Weedy Weed free Weedy Number of plants a 65 bc c 122 b 85 bc 66 bc 49 c Yield kg/ha 634 bc 875 ab 210 e 545 cd 327 de Plant vigour rating b 2.8 c 3.5 b 1.5 d 1.5 d 1.5 d

Linuron (PRE) 2.25 Bentazon (POST) d 0.96 Weed free control 314 a 1075 a 5.0 a Weedy control 259 a 579 c 4.9 a a 1000s/ha b Scale 0-5 with 0 = majority of plants dead, 5 = all plants healthy, uniform growth. Taken 29 days after planting. c Means not followed by a common letter differ significantly (P<0.05) d The POST application was 21 days after planting

The results of experiment 3 were as follows: · Weed competition in the weedy control reduced the yield by 46% when compared with the weed free control. · The yield following treatment with linuron (weed free) was not significantly less that the weed free control but linuron (weedy) reduced yield, possibly because of incomplete weed control. Both linuron treatments reduced plant population and vigor. · The combination with bentazon is toxic. In Nicaragua, Soto and Silva (1987) conducted plot trials at 2 sites in Nicaragua. C.v. China Roja sown in August was treated immediately with 1.4 or 2.1 l/ha Lorox-L (linuron). Assessment of weed and crop populations 15, 30, and 45 days after treatment showed that Dual gave the best control of grass weeds and Lorox-L gave best control of broadleaved weeds present; neither damaged the sesame; recommended rate of application for both herbicides was 2.1 1/ ha. In Egypt in Shandaweel, Ibrahim et al. (1988) studied the effect of 5 herbicides applied singly or in tank mixtures or hoeing on sesame crops infested with various weeds in 2 field trials in 198485. Treatments included 1.2 kg/ha linuron applied PRE individually, or as tank mixtures of alachlor or pendimethalin. Pendimethalin alone or with linuron or diuron gave excellent control of grass weeds, while linuron or diuron alone or mixed with pendimethalin effectively controlled

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broadleaved weeds. The best control of annual weeds and high seed yields and yield components resulted from treatment with pendimethalin alone or in tank mixtures with linuron or diuron. In Australia, a grower guide for South Burnett (Sapin et al. 2000) stated, "PRE herbicides which are used overseas and successfully in trials in Australia include linuron (Lorox)." In Mexico, a grower guide for Michoacan (Anon, 2007a) recommends the use linuron as a PRE in combination with alachlor as follows: Lasso afalon (1.0 lt + 0.5 kg) or Alanox + Linorox ( 1.5 lt +0.5 kg/ha). It is mixed with 250-300 liters of water. In Argentina in Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3 replications. There were 3 rains before emergence. The PRE test populations and weed control are as follows:

Weed control a 19 DDA b Herbicide Teliron Active ingredient Linuron Rate/ha 1.5 l 2.0 l

a a

30 DDA

Stand Ama Rha Ama Rha 3.9 90 85 90 95 3.9 90 90 85 100 Clean check 4.1 100 100 100 100 Weedy check 3.2 0 0 0 0 a Weed control with 0 = no control and 100 = complete control. Ama = Amaranthus quitensis and Rha = Raphanus sativus b DDA = days after application

There were four ratings done 19, 30, 60, and 88 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight of capsules in the center of the capsule zone. The number of seeds were counted and the seed weight per capsule (SWC) and was taken. The PRE data was as follows:

19 DDA Linuron low rate 90 Linuron high rate 85 Clean check 83 Weedy check 77 a DDA = days after application Active ingredient 30 DDA 88 85 87 77 60 DDA 100 90 88 78 88 DDA 97 83 82 72 Yield (g/m) 68.5 e 57.9 cde 59.9 de 53.8 bcde W100 (g) 0.320 0.302 0.284 0.297 Sd/cap 65 68 71 69 SWC (g) 0.208 0.205 0.202 0.205

Both linuron rates controlled the weeds and the yields were good ­ one better than the checks and the high rate comparable to the checks. This was the best PRE herbicide in the test. In Australia in the Northern Territories, Bennett (2007) stated that the research had concentrated on summer grass control. Since 1995 herbicide research has evaluated diuron, linuron, and Lontrel (clopyralid). Low rates of chemical applied PRE show promise but require further evaluation. POST OTT summary: No known research: POST DIR summary: In combination with diuron in Layby Pro was selective to sesame with no yield loss. Needs more research before using in farmer fields. In further testing in 2007 by itself and in combination with diuron.

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In the US in Texas, Grichar, Dotray, and Langham experimented with POST DIR treatments in Uvalde and Lubbock in 2006. The herbicides were applied 2" and 6" from the ground on both sides of the stem when the plants were about 18" tall in the juvenile stage. The treatments were replicated 3 times. In Uvalde the experiment was under a lateral pivot with extreme variation. As a result the yield data was taken by cutting a sample within the treatment and a sample in the adjacent untreated row. The yield below is a percent of the treated row divided by the untreated row. The Lubbock experiment was rainfed with some variation between rows, and the percentage yield below represents the treatment plot divided by the check plot. In both locations the day after planting, a PRE treatment of metolachlor plus glyphosate was sprayed over the fields. There was no weed pressure in either location since the purpose of the initial experiment was to find herbicides that would be selective to sesame.

Active ingredient Linuron and diuron Rate lbs/ ac 1.0 Height of applic 2" 6" Stunting Lub 0 0 Uva Yield % of check Lub Uva 100 126 89 88

Layby Pro appears to be promising, particularly because it has some residual action. In the US, the first author has made the following observations: · Linuron has been applied POST DIR in multiple passes when the sesame is in the early reproductive through mid bloom stages while it is still possible to get ground rigs into the fields. The linuron has controlled morningglory. The leaves at the bottom of the sesame were affected, but the plants did not die and there was no effect on the upper canopy. There was no side by side comparison with a control to see the effects on yields, but visually the crop terminated normally. Linuron characteristics: (Anon 1994, 1998) · Other crop uses: Has been used as PRE, POST, and POST DIR. It controls annual broadleaf weeds including mustard spp., pigweed spp., Florida pusley, purslane, Pennsylvania smartweed and certain grasses such as barnyard grass and foxtail spp. Foliar applications are effective on a wider spectrum of weeds. A nonionic surfactant increases the efficacy of applications to weed foliage. Linuron may be applied in liquid fertilizer. · Description: Light tan powdered solid, odorless. · Symptomology: With soil applications, seedlings emerge but become chlorotic within a few days, followed by complete necrosis. Foliar applications begin with interveinal chlorosis of the leaves and yellowing of their margins. Further chlorosis and necrosis follows in susceptible plants. Older leaves are more damaged than new growth. · Absorption/translocation: Absorbed readily into roots following soil application, but less so into leaves and stems when foliar-applied. It readily translocates upward in the xylem with little to no downward movement in the phloem. · Mechanism of action: Inhibits photosynthesis. · Sorption: Adsorption increases as soil clay or OM content increases. · Transformation: - Photodegradation: Probably insignificant losses except where soil is warm and no activating rainfall is received for several days or weeks. - Other degradation: Microbial breakdown is the primary means of dissipation. · Persistence: Average field half-life is 60 days, but ranges from 2-5 months. Linuron residues from spring applications do not injure cover crops planted the following fall. · Mobility: Leaching probably is not important factor. Leaches most in sand and least in soils high in clay or OM.

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· Volatilization: Negligible losses. · Miscellaneous information:

Common name Trade name Date Avg rate (lbs/ac) LD50 rat (mg/kg) Linuron Lorox 1964 1.75 1,196 Current sample of label: (http://www2.dupont.com/Production_Agriculture/en_US/products_services/herbicides/index.html)

Using the sample label above for Lorox DF, there are rotational restrictions from immediate to 4 months depending on the crop and the amount of the herbicide used. The following are the restrictions for the common crops in the sesame growing areas in the US as of 17 Jul 07, but refer to the current label for current restrictions East of the Rocky Mountains. · Any crop that is registered (field corn, sorghum, and soybeans) for the amount of linuron that was applied may be planted immediately. · Any crop may be planted after 4 months, except for cereals, where only barley, oats, rye, and wheat may be planted.

MESOTRIONE (Callisto)

PRE summary: No known research. POST over the time summary: Toxic to sesame with total kill in one test. In another test, substantial production reduction, but did not kill the sesame. In the US in South Texas, Grichar and Langham (2003) conducted a POST OTT test. A 5 ft swath of herbicides was sprayed across three rows of five lines leaving 15 ft of each row untouched to allow a direct within row comparison of the effects of the treatments. The herbicides were sprayed over the top in the juvenile stage when the plants were about 18" tall. There was a dual purpose: (1) find herbicides that were selective to sesame and (2) find herbicides that would control volunteer sesame in other crops. In this test, there were no weeds since the main thrust of the study was to look at the effects of the herbicide on the sesame. There were no replications in that the idea was to take the better lines and test them in Grichar et al. (2007). At the end of the ripening phase, the plots were evaluated in terms of percentage production compared to the untouched plants in the same row.

Treatment Mesotrione Rate 0.5x 1.0x Average S26 40 30 37 S27 40 50 49 S28 40 30 37 S29 60 60 48 132 30 40 31 Average 42 42 40

Mesotrione had a substantial reduction in production. In Argentina in Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3 replications. There were 3 rains before emergence. The POST OTT herbicides were applied 19 days after planting. The weed control data was taken 13 days after application and was as follows:

Herbicide Callisto Active ingredient Rate/ha Ama a Mesotrione 300 cc 100 Weed-free check 100 Weedy check 0 Weed control with 0 = no control and 100 = complete control. Rha = Raphanus sativus Rha a 100 100 0 Ama = Amaranthus quitensis and

a

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There were three ratings done 13, 43, and 70 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight from capsules in the center of the capsule zone. The number of seeds were counted and the seed weight per capsule (SWC) and was taken. The POST OTT data was as follows:

13 43 DDAa DDA Mesotrione 0 0 Weed-free check 81 83 Weedy check 75 71 a DDA = days after application Active ingredient 70 DDA 0 78 65 Yieldg (g/m) 48.4 ab 50.7 ab W100 (g) 0.300 0.300 Sd/cap SWC (g) 0.222 0.188

74.1 62.8

The mesotrione had complete weed and sesame control. POST DIR summary: No known research.

METHABENTHIAZURON (Tribunil)

PRE summary: No known research. POST OTT summary: Somewhat selective in that there is stunting but the plants recover to yield close to the check. In Australia in Queensland, Schrodter and Rawson (1984) evaluated PRE and POST herbicides on sesame grown under weed free and weedy conditions in Lockyer Valley in 4 experiments over two years. The variety Palmetto was used. The first two experiments were with PRE herbicides and the last two included POST herbicides. The POST applications were done 21 days after planting while the plants were in the third true leaf stage. The second POST experiment tried a few other POST herbicides with the following results

Herbicide Methabenthiazuron Rate kg/ha 0.7 1.4 Number of plants a 259 a c 236 a 312 a 290 a Yield kg/ha 928 ab 940 ab 937 ab 492 c Plant vigour rating b 2.7 c 2.7 c 5.0 a 5.0 a

Weed free control Weedy control a 1000s/ha b Scale 0-5 with 0 = majority of plants dead, 5 = all plants healthy, uniform growth. Taken 29 days after planting. c Means not followed by a common letter differ significantly (P<0.05)

The results of the experiment were as follows: Methabenzthiazuron produced yields and populations similar to the control treatments despite the observed effect on crop vigor. POST DIR summary: No known research.

METHAZOLE (Probe)

PRE summary: Mixed results with selective in one year and toxic in the next at the same rates.

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In the US, in California, St Andre (1973) conducted PPI trials under furrow irrigation, planted 15 May. Variety was 247 (nonshattering). Evaluated 14 Jun. Note that the stands are much lower than the other St Andre testing. Nonshattering (indehiscent) lines have much less vigor than semi-shattering or shattering lines.

Stand count a Herbicide Rate Sesame Sesame Mustard Japanese Pigweed lb/ac vigorb millet Probe (methazole) 2.0 9.8 12.2 0 3.5 1 4.0 8.0 9.0 0 0 0 Untreated --10 12.2 7.5 5.5 23 a Stand count values represent the average number of plants in 8 feet of row in 4 replications except for the pigweed which was only present in the 3rd replication. b Vigor evaluation is based on a 0-10 scale with 0 = very poor vigor and 10 = vigorous growing plants.

Methazole had little effect of the sesame stand or vigor, and it had better control of the mustard than most of the treatments although less control on the Japanese millet. In the US in California, St Andre (1974) conducted PPI (5-6.3 cm) trials under furrow irrigation, planted 28 May. Millet was seeded in the south half of each plot. Variety was Lucidi (shattering). Evaluated 13 Jul.

Percent Weed Sesame Sesame Percent control c vigor b vigor b stand a stand a 6/28 7/13 7/13 6/28 7/13 Probe (methazole) 2.0 4.5 6.7 56.2 62.5 9.2 4.0 2.0 4.5 23.7 17.2 6.7 Untreated --9.0 9.2 93.7 90.0 4.2/3.7 a Stands are based on an estimated percentage. Note that the untreated stands are not 100%. b Vigor evaluation is based on a 0-10 scale with 0 = very poor vigor and 10 = vigorous growing plants. c Ratings based on 0-10 scale. 0 = no control. 10 = perfect control. Herbicide Rate lb/ac

Although these are the same rates as used in 1973, the methazole did reduce the sesame vigor and stands substantially as opposed to the previous year. At a low rate, methazole had better weed control than at a high rate. POST summary: No known research.

METOBROMURON (Patoran.

Out of production in US

Galex is mix of metobromuron and metolachlor)

Sesame use: Used in commercial fields as PRE in form of Galex. No US label. PRE summary: Selective to sesame, particularly when mixed with Galex. In Bulgaria, Lyubenov and Kostadinov (1970) conducted trials in 1969 with sesame sown on chernozem smolnitsa soil on 29 May. PRE application of mixtures of 4 kg/ha Patoran (metobromuron) with 3 kg/ha Lasso (alachlor) or 5 kg/ha Ramrod (propachlor) gave effective control of weeds and increased seed yields and seed oil content. In Bulgaria, Georgiev (1980) concluded that on the basis of trials at Sadovo between 1974 and 1979, suitable herbicides for weed control in sesame included Patoran (metobromuron) at 2 kg/ha

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applied up to 2 days after sowing to control annual broadleaved weeds. The quality and fat content of sesame seeds were not adversely affected by these treatments. In Egypt, Hussien et al. (1983) studied metolachlor and Galex (metolachlor + metobrumuron) PRE. Two checks were used ­ one hand-hoed and the other with weeds. Galex was good on annual broadleaves and in controlling annual grasses. Galex at 1.8 kg/ha provided significant increases in seed yield/ha by 80 as compared to the unweeded check. Increase in seed yield by hand-hoeing was about 30% compared to the unweeded check. Seed oil content of sesame was not affected by the weed control treatments. Higher protein content was achieved with Galex at 1.8 kg/ha. In Nigeria, in a survey of agricultural crops (Anon 2004), it states, "The use of Galex (metolachlor + metobromuron) PRE for weed control were reported by two benniseed farmer cooperatives." POST summary: No known research.

METOLACHLOR (Dual, Allfire) and S-METOLACHLOR (Dual Magnum,

Medal) Sesame use: Used in commercial fields as PREPLANT or PRE. Somewhat toxic in one test as PPI. No label in US. PRE summary: Selective to sesame and good weed control. In further testing in 2007. Some work needs to be done to sort out which experiments were done with metolachlor and which were done with S-metolachlor In the US in California, St Andre (1978) conducted PPI trials (5-6.3 cm) under furrow irrigation, planted 22 May. Weeds present were barley, ground cherry, sowthistle, pigweed, and lambsquarter. Variety was Lucidi.

Herbicide Prefar (bensulide) Dual (metolachlor) Prefar (bensulide) + Dual (metolachlor) Devrinol (napropamide) + Dual (metolachlor) Dual (metolachlor) Furloe 124 (chlorpropham) Untreated

a b

Rate lb/ac 6.0 2.0 4.0 2.0 0.5 2.0 2.0 2.0 ---

Vigor 9.5 8.7 9.0 9.0 8.2 8.2 9.7

a

Grasses 6/13 3.7 6.0 1.5 7.0 7.2 7.2 0

Weed control b Grasses Broadleaf 6/22 6/13 3.25 9.0 6.5 9.7 2.0 9.7 7.5 7.0 7.0 .75 8.0 9.5 9.5 5.5

Broadleaf 6/22 8.0 6.75 8.5 8.5 5.5 5.5 5.75

Vigor scale ­ 0-10 with 0 = no vigor, 10 = excellent vigor Weed control scale 0-10 with 0 = no control, 10 = perfect control Metolachlor had a slight reduction in sesame vigor, but was only fair in overall weed control. It did provide good broadleaf control initially, but allowed broadleaves to germinate later.

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In Egypt, Hussien et al. (1983) studied metolachlor and Galex (metolachlor + metobrumuron) PRE. Two checks were used ­ one hand-hoed and the other with weeds. Galex was good on annual broadleaves while metolachlor and Galex showed superiority in controlling annual grasses. Galex at 1.8 kg/ha and metolachlor at 1.2 kg/ha provided significant increases in seed yield/ha by 80 and 45%, respectively as compared to the unweeded check. Increase in seed yield by hand-hoeing was about 30% compared to the unweeded check. Seed oil content of sesame was not affected by the weed control treatments. Higher protein content was achieved with Galex at 1.8 kg/ha. In the US in Arizona, Howell et al. (1984) had the following results:

Treat Herbicide PPI Dual (metolachlor) PRE Dual (metolachlor) PPI Dymid (diphenamid a) PPI + Dual (metolachlor) PRE Dymid (diphenamid a) PRE + Dual (metolachlor) PPI Prefar (bensulide) + PPI Dual (metolachlor) a out of production Rate /ac 3l 3l 4.8 kg 3l 4.8 kg 3l 5l 3l Mid stunt no/no OK/OK no/OK no/no no/no Mid stand OK/OK OK/OK OK/OK OK/OK OK/OK Broadleaf control OK/OK OK/OK OK/OK OK/OK OK/OK Grass control OK/OK OK/OK OK/OK OK/OK OK/OK Early vigor no/no OK/OK OK/OK OK/OK no/no

They concluded that PRE metolachlor was one of the best overall treatments, and only one of three treatments with OKs across the board. In combinations when the metolachlor was PRE there were no problems, but PPI metolachlor affected mid stunt and early vigor. In Korea, Kim et al. (1986) conducted field trials to study the herbicide efficacy and phytotoxicity in crops grown under polyethylene film. Most effective overall weed control was obtained 0.12 kg/ha Codal (metolachlor + prometryn) but it caused crop damage and yield reductions. In Nicaragua, Soto and Silva (1987) conducted plot trials at 2 sites in Nicaragua. C.v. China Roja sown in August was treated immediately with 1.4 or 2.1 l/ha Dual (metolachlor). Assessment of weed and crop populations was made 15, 30, and 45 days after treatment. Compared with 1.089 t in the untreated stand, 2.1 l/ha Dual had 2.224 t. Of the herbicides tested, Dual gave the best control of grass weeds and linuron gave best control of broadleaved weeds; neither damaged the sesame; recommended rate of application for both herbicides was 2.1 1/ ha. In Ethiopia, Zewdie (1994 applied four herbicides applied PRE and POST on sesame (Var Mahedo-80) during the 1991 and 1992 crop seasons to select appropriate herbicides for weed control in irrigated sesame. The results indicated that, next to hand weeding, at 30-35 days after crop emergence, the herbicide metolachlor (at 2.51 product/ha) was most effective against both grass and broadleaf weeds and resulted in a significant increase in sesame seed yield In Thailand, a field guide (Anon 1997) states that hand weeding is practiced twice at 15 and 25 days after emergence. The PRE herbicides metolachlor (1-1.25 l/ha) is also recommended in case of labor shortage. In Australia, Martin (1995) reported that metolachlor adequately controlled weeds but caused unacceptable crop injury. [Note that despite this assessment, most farmers and researchers in Australia use metolachlor as a PRE.]

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In the US in South Texas, Grichar et al. (2001a) conducted field studies from 1994 through 1997 in Yoakum and in Uvalde in 1995 to evaluate soil-applied herbicides for weed control, sesame tolerance, and yield. There were four replications. The varieties used were Sesaco 11, 17, or 18. The plant height was taken from averaging 5 plants and taken 5-7 weeks after planting. The data is as follows:

Herbicide Metolachlor Rate kg/ha 0.6 1.1 2.2 3.4 1.1 Applic PRE PRE PRE PRE PRE/30D b 1994 5 WAP a 38.7 46.5 43.4 16.9 Sesame height (cm) 1995 1996 7 WAP 6 WAP 123.7 50.8 125.7 53.6 119.1 48.0 124.0 50.5 122.2 51.5 131.3 43.4 31.0 11.6 1997 5 WAP 70.9 78.0 70.1 76.7 75.7 70.9 14.7

Check LSD (0.05) a WAP = weeks after planting b D = days after planting

Metolachlor had no effect on the height. In many cases the heights were higher than the check. The sesame population was counted 4-6 weeks after planting. The data was as follows:

Plants/m of row Herbicide Metolachlor Rate kg/ha 0.6 1.1 2.2 3.4 1.1 Applic PRE PRE PRE PRE PRE/30D 1995 62.8 84.0 91.8 60.0 61.8 70.3 23.5 1996 96.3 61.5 62.0 34.3 55.3 65.3 36.1 1997 50.1 48.6 a 58.5 59.1 67.8 67.5 18.8

Check LSD (0.05) a Significantly different from check

Overall, metolachlor increased and decreased populations but significantly decreased it in one trial. There was no pattern based on rate. The weed control is based on 0 = not control and 100 = complete control. The weed control data was as follows:

Herbicide Metolachlor Rate kg/ha 0.6 1.1 2.2 3.4 1.1 Applic PRE PRE PRE PRE PRE/30D Broadleaf signalgrass 94 91 0 21 Brown-top panicum 95 96 98 99 96 0 10 Southern cragrass 98 100 100 100 77 0 18 Palmer amaranth 1994 1995 92 85 0 25 95 99 100 100 100 0 4

Check LSD (0.05)

Imazepyr and metolachlor provide the most consistent weed control (>80%). The yield data was as follows:

Herbicide Metolachlor Rate kg/ha 0.6 1.1 2.2 3.4 1.1 Applic PRE PRE PRE PRE PRE/30D 1994 Yoakum 1170 a 860 650 1995 Yoakum 790 720 760 990 740 870 1995 Uvalde 1210 1190 1170 1520 a 1440 a 870 1996 Yoakum 830 660 730 910 550 480 1997 Yoakum 450 470 380 420 470 480

Check

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Rate Herbicide kg/ha Applic LSD (0.05) a Significantly different from check

1994 Yoakum 300

1995 Yoakum 310

1995 Uvalde 470

1996 Yoakum 450

1997 Yoakum 180

The data in the following table was converted to a percentage yield compared to the check, but the average did not include 1996 where all of the herbicides exceeded the yields of the check.

Herbicide Metolachlor Rate 1994 kg/ha Applic Yoakum 0.6 PRE 1.1 PRE 2.2 PRE 180 a 3.4 PRE 132 1.1 PRE/30D a Significantly different from check 1995 Yoakum 91 83 87 114 85 1995 Uvalde 139 137 134 175 a 166 a 1996 Yoakum 173 138 152 190 115 1997 Yoakum 94 98 79 88 98 Average 108 106 120 127 116

They concluded that metolachlor provided the best weed control and the least sesame injury. In Australia in the Northern Territories, a grower guide (Bennett 1998) states, "Grass weeds can be fairly easily controlled in a conventionally tilled sesame crop using PRE herbicides such as Dual." In Australia in South Burnett, a grower guide (Sapin et al. 2000) states, "PRE herbicides which are used overseas and successfully in trials in Australia include metolachlor (Dual)." O'Shanesy (2000) paralleled the above statements and in her production cost analysis showed the farmers using Dual. In Australia in the Northern Territories, Bennett (2003/2007, pers. commun.) stated: "We have no approved herbicides for sesame and need `minor crop' usage approval from the relevant authority. Dual works well on our sandy clay loams" In India in Rajasthan, Chandawat et al. (2004) conducted a field experiment to look at the efficacy of hand weeding 20 and/or 30 days after sowing (DAS) and 2 kg/ha metolachlor applied alone or in combination with hand weeding 30 DAS. Alachlor was the best treatment. In Nigeria, in a survey of agricultural crops (Anon 2004), it states, "The use of Galex (metolachlor + metobromulin [OP]) PRE for weed control were reported by two benniseed farmer cooperatives." In the US in Texas, Grichar and Dotray (2007) conducted PRE and POST OTT studies in two locations (Yoakum and Lubbock) in 2004 and 2005. The data from the PRE tests was as follows:

Rate Weed control Treat kg/ha AMATU BRAPP Check 0 0 S-metolachlor 1.42 99 91 S-metolachlor 1.50 90 56 + metribuzim 0.35 LSD (0.10) 15 28 40 25 29 29 18 217 a Bayer code for weeds: AMATU (Amaranthus tuberculatus) tall waterhemp, BRAPP (Brachiaria platyphylla) broadleaf signalgrass b Stand reduction and injury index: 0 = no stand reduction or sesame injury; 100 = complete stand reduction or plant death c Weed control and sesame yield taken at the Yoakum location only

a, c

Stand reduction b 2004 2005 Lub Yoa Yoa 0 0 0 0 9 0 49 100

Injury b 2004 2005 Lub Yoa 0 0 0 0 4

Yield c 2005 kg/ha 380 546 88

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They concluded that the plots had some of the highest yields, and parallels previous studies that have shown good results. They also combined S-metolachlor with metribuzim (Boundary at 0.35 kg/ha) and concluded that this combination is not viable as a PRE herbicide for sesame. In El Salvador, a growers guide (Anon 2007c) recommends 1.4 l/ha of metolachlor. In the US in South Carolina, Brad Sadler (2007, pers.commun.) has grown sesame for bird hunting for the past 20 years. He has used both Lasso (alachlor) and Dual (metolachlor) in alternating years in order to control yellow and purple nut sedge. He waits for a good probability of rain and then sprays the material and incorporates it before planting. He has had good stands with both materials. He has not noted any difference on the sesame with either product. In Australia Jim Barnes (2007, pers. commun.) stated: "PRE use of Dual (metolachlor) was OK but in our environment it requires incorporation which can be difficult. Some of our farmers were zero till farmers so incorporation was not possible, and Dual is unreliable unless you can guarantee follow up rain when applied post planting." In Argentina in Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3 replications. There were 3 rains before emergence. The PRE test populations and weed control are as follows:

Weed control a 19 DDA b Herbicide Dual

a a

30 DDA

Active ingredient Rate/ha Stand Ama Rha Ama Rha Metolachlor 1.2 l 2.5 100 40 70 50 Clean check 4.1 100 100 100 100 Weedy check 3.2 0 0 0 0 a Weed control with 0 = no control and 100 = complete control. Ama = Amaranthus quitensis and Rha = Raphanus sativus b DDA = days after application

There were four ratings done 19, 30, 60, and 88 days after application, yield samples and capsule data was taken on the better treatments that included the metolachlor. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight of capsules in the center of the capsule zone. The number of seeds were counted and the seed weight per capsule (SWC) and was taken. The PRE data was as follows:

19 DDA Metolachlor 73 Clean check 83 Weedy check 77 a DDA = days after application Active ingredient 30 DDA 78 87 77 60 DDA 63 88 78 88 DDA 73 82 72 Yield (g/m) 58.0 cde 59.9 de 53.8 bcde W100 (g) 0.289 0.284 0.297 Sd/cap 73 71 69 SWC (g) 0.211 0.202 0.205

The metolachlor produced a comparable yield to the checks, but it did not have as good weed control as one other herbicide, particularly on the Raphanus. In Australia in the Northern Territories, M. Bennett (2007) stated that the research had concentrated on summer grass control. Dual (metholachlor) applied at low rates (1.0 L/ha) on soils where sand content is less than 50 to 70% suppressed grass weed development with minimal reduction to sesame plant numbers.

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In the US and Argentina, the first author has made the following observations: · From 1998 through the present the practice in the Sesaco nurseries has been to pre-irrigate, harrow, plant the nurseries and experimental fields, and apply metolachlor and glyphosate within 2 days of planting. The glyphosate kills weeds that escaped the harrowing operation. In most years there is no rain until the sesame is up, but on two occasions, rain has activated the metolachlor and carried it into the soil, and the sesame plants came through it. There has never been a detectable difference in stand or injury, but a check without metolachlor has not been planted within the nurseries. · In some fields there is a difference in moisture across the field and while most of the seed is planted into moisture, some ends up in dry dirt. Applying a pivot across the field to activate the metolachlor, has brought up sesame to fill in the stands. It is assumed that the water imbibed by the seed had herbicide and that the layer of soil between the seed and the surface had herbicide. There was no digging of seedlings to determine if there were seedlings that had been damaged by the herbicide that did not emerge. · In one year, it rained about 10 mm before the metolachlor/glyphosate had been applied preventing the ground rig from entering the field. The metolachlor was chemigated on with a pivot about the time that the seedlings were emerging from the ground. The sesame that had been in dry soil germinated and emerged to form a good stand. There was no digging of seedlings to determine if they had been damaged by the herbicide and did not emerge. There was no damage to the seedlings that emerged. · In Argentina, metolachlor was applied on one field after planting and on three others before planting. All four fields had rains after planting and before seedling emergence. The stands on all of the fields which totaled 240 ha were excellent. The weed control initially was excellent, but with continual rains there were problems in two of the fields. In the first field, there was a rain between the PREPLANT application and three rains between planting and emergence. On this field, one field half was planted with metolachlor and the other half with trifluralin. The stands were similar, but there were less weeds in the half of the field with the metolachlor. In the other field, there was a flush of nabo (Raphanus sativus) about 3 weeks after planting. In this field, a full nabo crop was allowed to go to seed after the previous wheat crop. Any herbicide with 99% control of a weed will do reasonably well in the presence on millions of weed seeds, but will not look as effective in a field with hundreds of millions of weed seeds. In looking at the data from Lanfranconi, metolachlor does not show good weed control on rabo. · One of the concerns of metolachlor is that it takes rainfall (or irrigation) to activate it. The people that use it have the following philosophy: if there is a rain, it will be activated and will provide weed control, and if it does not rain, there is no need for weed control. The metolachlor does not provide control against later flushes of weeds, but by that time, the crop canopy has closed in and there are fewer problems with weeds. The exception is with weeds such as morningglory that come through weak light and climb the plants to reach the light. System summary: No effect on the sesame. Note that in Grichar (2001a) that metolachlor was applied 30 days after planting after an initial application of metolachlor. POST OTT summary: Can be applied over the top without any effect on sesame; however, will not control germinated weeds ­ only provides residual effect for new flushes of weeds. Note that in Grichar (2001a) that metolachlor was applied 30 days after planting after an initial application of metolachlor.

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In the US, Grichar and Dotray (2007) conducted POST OTT studies in two locations in Texas (Yoakum and Lubbock) in 2004 and 2005, but S-metolachlor was only tested in Lubbock. The herbicides were applied in the pre-reproductive stage when the plants were about 60 cm tall. The Lubbock trials were virtually weed free. The data from the tests was as follows:

Sesame injury (%) a Yield (kg/ha) Rate 2004 2005 2004 2005 Treatment b kg/ha Lub Yoa Lub Yoa Lub Lub Yoa Check 0 0 0 0 125 1,008 314 S-metolachlor 1.12 10 8 105 1,060 LSD (0.10) 11 36 20 105 226 a Injury index: 0 = no sesame injury; 100 = complete plant death. Ratings taken 6-8 wks after herbicide application b All herbicides included a non-ionic surfactant added at 0.25% v/v or a crop oil concentrate added at 1 qt/ac.

Their conclusions were as follows: · In Lubbock where there were no weeds, the treatment was the only one that did not reduce the yield of the sesame. · The treatment caused very little injury to the sesame. In the US in South Carolina, Brad Sadler (2007, pers.commun.) has grown sesame for bird hunting for the past 20 years. In a few years he has sprayed Dual (metolachlor) over the top of the seedlings and found some set back. However, at the end there was a normal crop. In the US, the first author has made the following observations: · Metolachlor is normally used as a PRE, but in one year it rained 10 mm after planting before the herbicide could be applied. The metolachlor was then applied through a pivot as the sesame was emerging and with just cotyledons. Observing the field before and after application, there was no effect on the emerged plants and additional seedlings emerged. POST DIR summary: No known research. Metolachlor characteristics: (Anon 1994, 1998) · Other information: There are two isomers of metolachlor: S-metolachlor and R-metolachlor. Both are effective against weeds, but S-metolachlor is more effective at a lower rate (35% less active ingredient). The initial Dual had close to equal ratios of the isomers while Dual Magnum had a higher proportion of S-metolachlor. With the introduction of generics, it is important to look at the labels since companies use different safeners (benoxacor and/or atrazine) which also may have an effect of the crop. To date, the US sesame research has been done with Dual and Dual Magnum, but many papers do not cite the trade name of the chemical used in the research. Dual was introduced in 1977 and Dual Magnum in 1997. It is assumed that all research done after 1997 was with Dual Magnum. · Other crop uses: Used as early PREPLANT, PRE, PPI, POST. Controls most yellow nutsedge and many annual grasses such as foxtail, barnyardgrass, crabgrass, fall panicum, signalgrass, witchgrass, and red rice. Also controls certain broadleaf weeds such as redroot pigweed, carpetweed, and Florida pusley. Does not control seedling johnsongrass, shattercane, or Texas panicum. Metolachlor can be applied through center pivot irrigation systems. Can also be applied in liquid or dry bulk fertilizer. · Description: white to tan liquid, odorless. · Symptomology: Most susceptible weeds fail to emerge from the soil. Injury to grasses appears as malformed and twisted seedlings. Leaves are tightly rolled in the whorl and my not unroll

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·

· · ·

· · · ·

properly. Injured broadleaf weeds have cupped or crinkled leaves with a drawstring or heart shaped appearance. Absorption/translocation: Absorbed by emerging shoots (grass coleoptile, broadleaf hypocotyl or epicotyl). Some root absorption occurs also. Plants beyond the seedling stage can absorb into roots and translocate to the shoots through the xylem and phloem and can accumulate in the vegetative parts and less in the reproductive parts. However, it is phytotoxic only to emerging weed seedlings. Mechanism of action: S-metolachlor inhibits the biosynthesis of several plant components such as fatty acids, lipids, proteins, isoprenoids, and flavonoids. Sorption: Moderately adsorbed to soil. It more readily absorbs to muck or clay soils than to soils with low OM or clay content. Transformation: - Photodegradation: Half-life in water was 70 days at 8-45°C and pH 7 with natural light and 8 days on sandy loam soil at 15-52°C. Photodegradation is a major contributor to dissipation in the field, particularly under prolonged lack of rainfall when it remains on the soil surface. - Other degradation: Half-life was 67 to 81 days for aerobic microbial metabolism. Microbial degradation is the major contributor to dissipation where it has moved beneath the soil surface. Non-biological degradation is negligible. Persistence: Generally provides 10-14 weeks of weed control. Residues do not persist long enough to affect crops planted the following season. Field half-life is generally 3-5 months. Mobility: In field experiments in Wisconsin, no quantifiable residues were found below 45 cm. Volatilization: Generally low, but losses can be significant under certain conditions. Miscellaneous information:

Common name Trade name Date Avg rate (lbs/ac) LD50 rat (mg/kg) Metolachlor Dual, Bicep 1977 2.75 2,534 Current sample of label: (http://www.syngentacropprotection-us.com/prod/herbicide/Dualmagnum/).

Using the sample label above for Dual magnum, there are rotational restrictions from immediate to 18 months depending on the crop and the amount of the herbicide used. The following are the restrictions for the common crops in the sesame growing areas in the US as of 18 Jul 07, but refer to the current label for current restrictions. · If crop treated is lost, any crop on the label (corn, cotton, peanuts, sorghum, soybeans) may be planted immediately. Do not apply second application. · Barley, oats, rye, or wheat may be planted 4.5 months after treatment. · Alfalfa may be planted 4 months after treatment. · Do not graze or feed forage or fodder from cotton to livestock.

METRIBUZIM (Sencor, Sencorex)

PRE summary: Toxic to sesame with substantial reduction in yield and stand. In the US, in California, St Andre (1973) conducted PPI trials under furrow irrigation, planted 15 May. Variety was 247 (non-shattering). Evaluated 14 Jun. Note that the stands are much lower than the other St Andre testing. Non-shattering (indehiscent) lines have much less vigor than semi-shattering or shattering lines.

Herbicide Sencor (metribuzim) Rate lb/ac 0.5 1.0 Sesame vigorb 7.8 7.3 Sesame 7.0 0.5 Stand count a Mustard Japanese millet 0.5 4.2 0 1.2 Pigweed 0 0

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Stand count a Herbicide Rate Sesame Sesame Mustard Japanese Pigweed lb/ac vigorb millet Untreated --10 12.2 7.5 5.5 23 a Stand count values represent the average number of plants in 8 feet of row in 4 replications except for the pigweed which was only present in the 3rd replication. b Vigor evaluation is based on a 0-10 scale with 0 = very poor vigor and 10 = vigorous growing plants.

Metribuzim reduced stands substantially, particularly at the high rate. The sesame vigor ratings were among the lowest in the test. There was good control of the mustard and pigweed, but little control of the Japanese millet. In the US in Texas, Grichar and Dotray (2007) conducted PRE studies in two locations in Texas (Yoakum and Lubbock) in 2004 and 2005. The data from the tests was as follows:

Rate Weed control Treat kg/ha AMATU BRAPP Check 0 0 Flufenacet + 0.14 89 66 metribuzim 0.21 S-metolachlor 1.50 90 56 49 100 4 + metribuzim 0.35 LSD (0.10) 15 28 40 25 16 29 29 18 11 a Bayer code for weeds: AMATU (Amaranthus tuberculatus) tall waterhemp, BRAPP (Brachiaria platyphylla) broadleaf signalgrass b Stand reduction and injury index: 0 = no stand reduction or sesame injury; 100 = complete stand reduction or plant death c Weed control and sesame yield taken at the Yoakum location only

a, c

Stand reduction b 2004 2005 Lub Yoa Lub Yoa 0 0 0 0 74 49

Injury b 2004 2005 Lub Yoa Lub 0 0 0 25 -

Yield c 2005 kg/ha 380 305 88 217

They concluded that flufanacet plus metribuzim is not viable as a PRE herbicide for sesame even though the yield is 80% of the check because of the damage to the sesame. They also combined metribuzim with S-metolachlor (Boundary) and concluded that this combination is not viable as a PRE herbicide for sesame. In Argentina in Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3 replications. There were 3 rains before emergence. The PRE test populations and weed control are as follows:

Weed control a 19 DDA b Herbicide Sencorex 30 DDA Active ingredient Rate/ha Stand Ama a Rha a Ama Rha Metribuzim 700 cc 1.3 100 65 100 60 Clean check 4.1 100 100 100 100 Weedy check 3.2 0 0 0 0 a Weed control with 0 = no control and 100 = complete control. Ama = Amaranthus quitensis and Rha = Raphanus sativus b DDA = days after application

There were four ratings done 19, 30, 60, and 88 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight of capsules in the center of the capsule zone. The number of seeds were counted and the seed weight per capsule (SWC) and was taken. The PRE data was as follows:

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Active ingredient

19 DDA Metribuzim 7 Clean check 83 Weedy check 77 a DDA = days after application

30 DDA 17 87 77

60 DDA 5 88 78

88 DDA 8 82 72

Yield (g/m) 59.9 de 53.8 bcde

W100 (g) 0.284 0.297

Sd/cap 71 69

SWC (g) 0.202 0.205

Metribuzim substantially reduced the population and still did not provide adequate weed control. POST summary: No known research.

METSULFURON-METHYL (Ally)

PRE summary: No known research, but mixed results in planting sesame after herbicide used in previous cereal crop. In the US, there are many wheat farmers that apply sulfuron products late in the wheat crop to control broadleaf weeds. There are been mixed results in planting sesame after these products. POST summary: No known research.

MONOLINURON (Afesin)

PRE summary: Somewhat selective to sesame at lower rates and toxic at higher rates. In Trinidad, Weiss (1971) cites L. Kasasian (1967, 1968) that did the following work.

Herbicide Weedfree control Monolinuron Monolinuron + Diphenamid Rate (kg/ha) 1.1 2.2 1.1 2.2 Percent yield 100 89 53 61

POST summary: No known research.

MONURON (Monurex, Telvar) Out of production in US

PRE summary: Selective to sesame with good weed control. In the US, Culp and McWhorter (1965) cited Tocquigny and Livingston (1953) that monuron was promising for use in sesame. In the US, Weiss (1971) cited Martin (1963, 1964) who reported that monuron at 0.18 and 0.40 kg/ha PRE gave good control of weeds, with no injury to sesame at the lower rate and no significant reduction in yield.

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In Venezuela, Weiss (1971) cited Mazzani (1966) that monuron applied PRE at 1 kg/ha gave reasonable control of weeds with no effect on the crop. POST summary: No known research.

NAPROPAMIDE (Devrinol, Pamid)

PRE summary: Selective to sesame as a PRE at a low rate, but toxic as a PPI or at a higher rate. In the US, in California, St Andre (1973) conducted PPI trials under furrow irrigation, planted 15 May. Variety was 247 (nonshattering). Evaluated 14 Jun. Note that the stands are much lower than the other St Andre testing. Nonshattering (indehiscent) lines have much less vigor than semi-shattering or shattering lines.

Stand count a Herbicide Rate Sesame Sesame Mustard Japanese Pigweed lb/ac vigorb millet Devrinol (napropamide) 1.0 9.0 14.5 10.0 0.2 3 2.0 6.5 10.0 10.2 0.2 0 Untreated --10 12.2 7.5 5.5 23 a Stand count values represent the average number of plants in 8 feet of row in 4 replications except for the pigweed which was only present in the 3rd replication. b Vigor evaluation is based on a 0-10 scale with 0 = very poor vigor and 10 = vigorous growing plants.

Napropamide at the low rate had little effect on the stand and vigor of sesame, but at the high rate it reduced the vigor. The weed control for all but mustard was excellent. In the US in California, St Andre (1974) conducted PPI (5-6.3 cm) trials under furrow irrigation, planted 28 May. Millet was seeded in the south half of each plot. Variety was Lucidi (shattering). Evaluated 13 Jul.

Herbicide Rate lb/ac Sesame vigor b 6/28 9.0 Sesame vigor b 7/13 8.2 Percent stand a 6/28 95.0 Percent stand a 7/13 87.5 Weed control c 7/13 ---

Devrinol (napropamide) + 1.0 Enide (diphenamid) 4.0 Devrinol (napropamide) + 1.0 2.7 6.0 30.0 17.5 9.7 Lasso (alachlor) 2.0 Untreated --9.0 9.2 93.7 90.0 4.2/3.7 a Stands are based on an estimated percentage. Note that the untreated stands are not 100%. b Vigor evaluation is based on a 0-10 scale with 0 = very poor vigor and 10 = vigorous growing plants. c Ratings based on 0-10 scale. 0 = no control. 10 = perfect control.

In combination with diphenamid, napropamide had little effect on the sesame vigor or stand, but in combination with alachlor there was a substantial reduction in vigor and stand. In the US in California, St Andre (1978) conducted PPI trials (5-6.3 cm) under furrow irrigation, planted 22 May. Weeds present were barley, ground cherry, sowthistle, pigweed, and lambsquarter. Variety was Lucidi.

Herbicide Lasso (alachlor) + Rate lb/ac 2.0 Vigor 10

a

Grasses 6/13 7.5

Weed control b Grasses Broadleaf 6/22 6/13 5.75 10

Broadleaf 6/22 8.0

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Herbicide Devrinol (napropamide) Devrinol (napropamide) + Dual (metolachlor) Untreated

a

Rate lb/ac 0.5 0.5 2.0 ---

Vigor

a

Grasses 6/13 7.0 0

Weed control b Grasses Broadleaf 6/22 6/13 7.5 .75 8.0 5.5

Broadleaf 6/22 8.5 5.75

9.0 9.7

Vigor scale ­ 0-10 with 0 = no vigor, 10 = excellent vigor b Weed control scale 0-10 with 0 = no control, 10 = perfect control Napropamide did not have an effect of the vigor of the sesame. It had good weed control on the broadleaves including residual effect which neither the alachlor or metolachlor have. However, it only slightly increased the effectiveness against grasses. In Israel, Graph et al. (1985) showed that PPI application of napropamide caused severe crop damage. In Korea, Kim et al. (1986) conducted field trials to study the herbicide efficacy and phytotoxicity in crops grown under polyethylene film. 3 l/ha napropamide or 1.5 l/ha alachlor gave sesame yields equivalent to that obtained with manual weed control, whereas the other herbicides caused crop damage and yield reductions. In Korea, a research summary (Lee 1986) recommended Pamid WD (napropamide). POST summary: No known research.

NAPTALAM ­ NPA (Alanap)

PRE summary: Toxic to sesame. In the US in California, Fischer (1971) summarized the work that had been done between 1967 and 1970 in the San Joaquin valley to include the results of St Andre (1969, 1970a, and 1970b). In that area the concept was to grow sesame double cropped after barley or other cereals, and thus the emphasis was on controlling volunteer grasses. He summarized the results for the years as follows:

Trade name Alanap Active ingredient Naptalam Lbs/ac evaluated 5.0 Sesame tolerance Poor Barley control Poor

POST OTT summary: Toxic to sesame with severe stunting, but the sesame recovered in one test. In the US, Culp and McWhorter (1965) cited Tocquigny and Livingston (1953) that naptalam (NPA) and mixture of NPA and NPA imide caused slight to severe stunting. However, most of the plants essentially overcame the stunted condition before harvest. In the US in Mississippi, Culp and McWhorter (1965) cited Culp and Holstun (1958) that sesame was severely injured by naptalam (NPA) at 2 and 4 lb/ac. POST DIR summary: No known research.

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NICOSULFURON (Accent)

PRE summary: No known research, but mixed results in planting sesame after herbicide used in previous cereal crop. In the US, there are many wheat farmers that apply sulfuron products late in the wheat crop to control broadleaf weeds. There are been mixed results in planting sesame after these products. POST OTT summary: Toxic to sesame with substantial production reduction, but did not kill the sesame. In the US in South Texas, Grichar and Langham (2003) conducted a POST OTT test. A 5 ft swath of herbicides was sprayed across three rows of five lines leaving 15 ft of each row untouched to allow a direct within row comparison of the effects of the treatments. The herbicides were sprayed over the top in the juvenile stage when the plants were about 18" tall. There was a dual purpose: (1) find herbicides that were selective to sesame and (2) find herbicides that would control volunteer sesame in other crops. In this test, there were no weeds since the main thrust of the study was to look at the effects of the herbicide on the sesame. There were no replications in that the idea was to take the better lines and test them in Grichar et al. (2007). At the end of the ripening phase, the plots were evaluated in terms of percentage production compared to the untouched plants in the same row.

Treatment Nicosulfuron Rate 0.5x 1.0x Average S26 30 20 37 S27 60 20 49 S28 40 20 37 S29 60 40 48 132 60 10 31 Average 50 22 40

Nicosulfuron had a substantial reduction in production. POST DIR summary: No known research.

NITRALIN (Planavin)

Out of production in US

PRE summary: Mixed results with selective in one test and toxic in another. In the US in California, Fischer (1971) summarized the work that had been done between 1967 and 1970 in the San Joaquin valley to include the results of St Andre (1969, 1970a, and 1970b). In that area the concept was to grow sesame double cropped after barley or other cereals, and thus the emphasis was on controlling volunteer grasses. He summarized the results for the years as follows:

Trade name Planavin Active ingredient Nitralin Lbs/ac evaluated 0.75/1.0 Sesame tolerance Poor Barley control Erratic

In Egypt, Hussien et al. (1983) studied nitralin PPI. Two checks were used ­ one hand-hoed and the other with weeds. Nitralin showed superiority in controlling annual grasses. The most harmful treatments in descending order were nitralin at 2.7 and 1.8 kg/ha. Seed oil content of sesame was not affected by the weed control treatments. Higher protein content was achieved with nitralin at 1.8 and 2.7 kg/ha. POST summary: No known research.

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NITROFEN

Out of production in US

PRE summary: Toxic to sesame. In India, Ghosh and Mukhopadhyay (1980) carried out field experiments during the kharif season of 1979 that showed that nitrofen at 1 and 2 kg/ha PRE, though effective against weeds, was also not well tolerated by sesame. In India, Shukla (1984) found that application of nitrofen was toxic to the crop. A spray of 1 l/ha of propanil (Stam-F34) before sowing sesame gave effective control of weeds and resulted in seed yields of 127.5 kg/ha. POST summary: No known research.

NOREA (Herban)

Out of production in US

PRE summary: Mixed results with selective at low rates, and toxic at higher rates. In the US in South Carolina, Culp and McWhorter (1965) cited Martin and Crawford (1963) who reported that norea caused slight to severe damage to sesame, but when it was tried at lower rates it did not cause visible plant injury and gave weed control essentially equivalent to that obtained with CIPC. In Trinidad, Weiss (1971) cites L. Kasasian (1967, 1968) that trials over several years showed norea to be a highly effective herbicide in sesame. In a PRE trial, norea at 6.6 kg/ha outyielded the control, but a 4.4 and 2.2 kg/ha was decreasingly effective. A combination of 3.3 kg/ha norea plus 3.3 kg/ha diphenamid was also less effective than 7 kg/ha of norea. He also provides the following table on yield using norea.

Herbicide Weedfree control Norea Rate (kg/ha) 2.2 4.5 Percent yield 100 88 74

In the US in California, St Andre (1970a) conducted PPI trials under furrow irrigation, planted 14 May. Variety was 215 (semi-shattering). Evaluated 2 Jun.

Herbicide Rate Sesame Grass lb/ac Herban (norea) 2.0 110.0 0 1.0 4.0 4.0 83.6 0 0 1.6 Untreated --96.0 6.6 1.3 58.3 a Stand count values represent the average number of plants in 8 feet of row b Ratings based on 0-10 scale. 0 = no control or injury. 10 = perfect control or very severe injury. Injury rating reflects retardation and vigor in the growth of sesame. Stand count a Pigweed Mustard Visual rating b Weed Sesame control injury 9.5 0.3 10 4.0 0 0

Herban had the least effect on the sesame stand, negligible injury, and good weed control.

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In the US in California, St Andre (1970b) conducted PPI (5-6.3 cm) trials under furrow irrigation, planted 25 Jun. Stand counts were done 14 Jul and the ratings 18 Jul. The barley was harvested, disked in, listed, and preirrigated. Herbicides were applied and incorporated in the same operation with planting.

Visual ratingb Herbicide Rate Barley Sesame lb/ac control injury Herban (norea) 1.5 87.5 12.3 4.6 0 3.0 53.0 6.6 6.0 1.0 Untreated --81.0 14.0 1.6 0.6 a Stand count values represent the average number of plants in 8 feet of row b Ratings based on 0-10 scale. 0 = no control or injury. 10 = perfect control or very severe injury. Injury rating reflects retardation and vigor in the growth of sesame. Stand counta Sesame Barley

Herban at the low rate had little effect on the sesame, but did not control the barley; at a higher rate it had more effect on the sesame, but although more control on the barley, was not as good as the other treatments. In the US in California, Fischer (1971) summarized the work that had been done between 1967 and 1970 in the San Joaquin valley to include the results of St Andre (1969, 1970a, and 1970b). In that area the concept was to grow sesame double cropped after barley or other cereals, and thus the emphasis was on controlling volunteer grasses. He summarized the results for the years as follows:

Trade name Herban Active ingredient Norea Lbs/ac evaluated 1.5/3.0 Sesame tolerance Fair Barley control Poor

Their overall evaluations was that norea at 2 lbs/ac looked promising, but caused some stand reduction and growth retardation at 4 lbs/ac and did not provide effective control of volunteer barley. POST summary: No known research.

NORFLURAZON (Zorial, Solicam)

PRE summary: Toxic to sesame with substantial stand reduction and injury. In the US in Texas, Grichar and Dotray (2007) conducted PRE and POST OTT studies in two locations (Yoakum and Lubbock) in 2004 and 2005. The data from the PRE tests was as follows:

Stand reduction b Injury b Yield c Rate Weed control 2004 2005 2004 2005 2005 Treat kg/ha AMATU BRAPP Lub Yoa Yoa Lub Yoa kg/ha Check 0 0 0 0 0 0 0 380 Norflurazon 1.12 58 28 LSD (0.10) 15 28 40 25 29 29 18 217 a Bayer code for weeds: AMATU (Amaranthus tuberculatus) tall waterhemp, BRAPP (Brachiaria platyphylla) broadleaf signalgrass b Stand reduction and injury index: 0 = no stand reduction or sesame injury; 100 = complete stand reduction or plant death c Weed control and sesame yield taken at the Yoakum location only

a, c

They concluded that norflurazon is not a good PRE herbicide for sesame. POST summary: No known research.

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OXADIAZON (Ronstar)

PRE summary: Somewhat selective to sesame in that there is stand reduction, but the plants recover well at the end. Not as good as other treatments. In the US in California, St Andre (1973) conducted PPI trials under furrow irrigation, planted 15 May. Variety was 247 (nonshattering). Evaluated 14 Jun. Note that the stands are much lower than the other St Andre testing. Nonshattering (indehiscent) lines have much less vigor than semi-shattering or shattering lines.

Stand count a Herbicide Rate Sesame Sesame Mustard Japanese Pigweed lb/ac vigorb millet Ronstar (oxadiazon) 2.0 9.3 14.2 10.2 18.7 17 4.0 10 13.5 6.0 9.2 23 Untreated --10 12.2 7.5 5.5 23 a Stand count values represent the average number of plants in 8 feet of row in 4 replications except for the pigweed which was only present in the 3rd replication. b Vigor evaluation is based on a 0-10 scale with 0 = very poor vigor and 10 = vigorous growing plants.

Oxadiazon had little effect on the sesame stand or vigor, but it also had one of the worst controls for weeds. In Argentina in Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3 replications. There were 3 rains before emergence. The PRE test populations and weed control are as follows:

Weed control a 19 DDA b Herbicide Ronstar Active ingredient Oxadiazon Rate/ha 1.3 l 2.0 l

a a

30 DDA

Stand Ama Rha Ama Rha 1.8 95 55 85 65 1.8 95 55 95 80 Clean check 4.1 100 100 100 100 Weedy check 3.2 0 0 0 0 a Weed control with 0 = no control and 100 = complete control. Ama = Amaranthus quitensis and Rha = Raphanus sativus b DDA = days after application

There were four ratings done 19, 30, 60, and 88 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight of capsules in the center of the capsule zone. The number of seeds were counted and the seed weight per capsule (SWC) and was taken. The PRE data was as follows:

19 DDA Oxadiazon low rate 10 Oxadiazon high rate 5 Clean check 83 Weedy check 77 a DDA = days after application Active ingredient 30 DDA 12 5 87 77 60 DDA 48 53 88 78 88 DDA 53 47 82 72 Yield (g/m) 38.0 abc 38.1 abc 59.9 de 53.8 bcde W100 (g) 0.290 0.287 0.284 0.297 Sd/cap 67 63 71 69 SWC (g) 0.194 0.181 0.202 0.205

Oxadiazon reduced the yields substantially and did not control the weeds adequately.

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POST OTT summary: Without a surfactant, somewhat toxic initially, but the plants recovered well. With a surfactant, toxic to sesame. In further testing in 2007. In Argentina in Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3 replications. There were 3 rains before emergence. The POST OTT herbicides were applied 19 days after planting. The weed control data was taken 13 days after application and was as follows:

Herbicide Ronstar Active ingredient Rate/ha Ama a Rha a Oxadiazon 1300 cc 50 30 Weed-free check 100 100 Weedy check 0 0 Weed control with 0 = no control and 100 = complete control. Ama = Amaranthus quitensis and Rha = Raphanus sativus

a

There were three ratings done 13, 43, and 70 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight from capsules in the center of the capsule zone. The number of seeds were counted and the seed weight per capsule (SWC) and was taken. The POST OTT data was as follows:

13 43 DDAa DDA Oxadiazon 53 88 Weed-free check 81 83 Weedy check 75 71 a DDA = days after application Active ingredient 70 DDA 78 78 65 Yieldg (g/m) 51.2 ab 48.4 ab 50.7 ab W100 (g) 0.282 0.300 0.300 Sd/cap 64.6 74.1 62.8 SWC (g) 0.182 0.222 0.188

The ozadiazon did not have good weed control and injured the sesame. However, the sesame recovered and through branching ended up with a good stand. The end yields were comparable to the checks. POST DIR summary: No known research.

OXASULFURON (GCA, Dynam)

PRE summary: No known research. POST OTT summary: Toxic to sesame with substantial reduction in production. In the US in South Texas, Grichar and Langham (2003) conducted a POST OTT test. A 5 ft swath of herbicides was sprayed across three rows of five lines leaving 15 ft of each row untouched to allow a direct within row comparison of the effects of the treatments. The herbicides were sprayed over the top in the juvenile stage when the plants were about 18" tall. There was a dual purpose: (1) find herbicides that were selective to sesame and (2) find herbicides that would control volunteer sesame in other crops. In this test, there were no weeds since the main thrust of the study was to look at the effects of the herbicide on the sesame. There were no replications in that the idea was to take the better lines and test them in Grichar et al. (2007). At the end of the ripening phase, the plots were evaluated in terms of percentage production compared to the untouched plants in the same row.

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Treatment GCA

Rate 0.5x 1.0x Average

S26 10 20 37

S27 30 60 49

S28 20 40 37

S29 30 60 48

132 20 30 31

Average 22 42 40

GCA was one of the few treatments that had a more severe production reduction at the low rate than the upper rate. This was noted prior to harvest and verified. The results are still severe production reduction at both rates. POST DIR summary: No known research.

OXYFLUORFEN (Goal)

PRE summary: Somewhat selective to sesame and good weed control, but other treatments were better. In India in Uttar Pradesh, Om et al. (2001) investigated the effects of N fertilizer application and weed control measures on sesame during 1995 and 1996. Treatments consisted of N levels, i.e. 0, 30, 60 and 90 kg/ha, and weed control treatments, i.e. weedy control, hand weeding 3 weeks after sowing, PRE application of oxyfluorfen (0.15 kg/ha) + hand weeding. N fertilizer rate did not significantly affect the weed population. Other treatments were better. In India in Tamil Nadu, Gnanavel and Anbhazhagan (2006) conducted a field experiment in summer 2002 to evaluate the efficacy of different PRE herbicides and herbicide along with hand weeding (HW) in controlling weeds in irrigated sesame (cv. TMV 5). The treatments included 0.25 kg/ha oxyfluorfen and 0.15 kg/ha oxyfluorfen + HW at 30 DAS. The application of 0.15 kg/ha oxyfluorfen with one HW at 30 DAS was significantly better in terms of weed control index (92.7%) and seed yield (0.92 t/ha). POST OTT summary: Toxic to sesame with substantial production reduction, but did not kill the sesame. In the US in South Texas, Grichar and Langham (2003) conducted a POST OTT test. A 5 ft swath of herbicides was sprayed across three rows of five lines leaving 15 ft of each row untouched to allow a direct within row comparison of the effects of the treatments. The herbicides were sprayed over the top in the juvenile stage when the plants were about 18" tall. There was a dual purpose: (1) find herbicides that were selective to sesame and (2) find herbicides that would control volunteer sesame in other crops. In this test, there were no weeds since the main thrust of the study was to look at the effects of the herbicide on the sesame. There were no replications in that the idea was to take the better lines and test them in Grichar et al. (2007). At the end of the ripening phase, the plots were evaluated in terms of percentage production compared to the untouched plants in the same row.

Treatment Oxyfluorfen Rate 0.5x 1.0x Average S26 40 30 37 S27 40 30 49 S28 30 20 37 S29 30 30 48 132 30 30 31 Average 34 28 40

Oxyfluorfen reduced production substantially, but did not kill the sesame. POST DIR summary: No known research.

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PARAQUAT (Gramoxone)

Sesame use: Potential use as a POST DIR to control weeds, but will not provide residual control. PRE summary: No known research. POST OTT summary: Burns the leaves, but the yield is close to the check at the end. In Somalia, Malik and Ramzan (1992) conducted field studies during April-June and OctoberDecember 1989, to examine the efficacy and yield of the POST Gramoxone 20EC (paraquat) at 1.5 l/ha as compared to hand weeding for the control of weeds infesting sesame. The results showed that all herbicides and hand weeding gave an effective level of control. Greatest weed control was obtained using PRE Stomp (86.04%), followed by hand weeding (84.97%) and Gramoxone (81.34%). POST DIR summary: Burns the leaves, but the yield is close to the check at the end. The major problem is that it is very volatile and commercial applicators are hesitant to use it in areas with multiple crops, particularly vegetables. In further testing in 2007. In Australia in South Burnett, a grower guide (Sapin et al. 2000) states that sesame will not tolerate paraquat. In the US in Texas, Grichar et al. (2006) experimented with POST DIR treatments in Uvalde and Lubbock in 2006. The experiment is being repeated in 2007. The variety used was Sesaco 29 planted 25 May in Uvalde and 20 June in Lubbock. The herbicides were applied 2" and 6" from the ground on both sides of the stem when the plants were about 18" tall in the juvenile stage. The treatments were replicated 3 times. In Uvalde the experiment was under a lateral pivot with extreme variation. As a result the yield data was taken by cutting a sample within the treatment and a sample in the adjacent untreated row. The yield below is a percent of the treated row divided by the untreated row. The Lubbock experiment was rainfed with some variation between rows, and the percentage yield below represents the treatment plot divided by the check plot. In both locations the day after planting, a PRE treatment of metolachlor plus glyphosate was sprayed over the fields. There was no weed pressure in either location since the purpose of the initial experiment was to find herbicides that would be selective to sesame.

Active ingredient Paraquat Rate lbs/ ac 0.25 Height of applic 2" 6" Stunting Lub 0 0 Uva Yield % of check Lub Uva 103 98 84 88

Paraquat shows immediate burning of sesame leaves, but the plants survive and there is little yield reduction particularly at 2". It may show some promise in burning down existing weeds. However, it will not have a residual effect. Must be applied carefully if there is a wind because the herbicide will burn down leaves higher than the level of application ­ when applying when the plants were 23" tall, some of the upper leaves had drift damage. Harvest aid summary: Mixed results in that it burns all areas that come in contact with it, but in some areas it will kill the plant and thus dry it down, and in other areas, will not kill the plant. Needs much more research before farmer use.

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PEBULATE (Tillam)

PRE summary: Somewhat selective to sesame and good weed control, but other treatments were better In the US in Mississippi, Culp and McWhorter (1965) tried 13 herbicides at different rates on sesame and four different weeds in the greenhouse. They concluded that although pebulate (PEBC) and chlorpropham (CIPC) both provided good weed control and had 15% or less injury on the sesame that CIPC was chosen for further experiments because it could be readily applied with conventional farm equipment. POST summary: No known research.

PENDIMETHALIN (Prowl, Stomp.

require PPI)

Prowl H2O, Herbadox, and Pendimax do not

Sesame use: Used in commercial fields as PPI and POST. No label in US. PRE summary: Mixed results ­ selective to sesame and very good weed control, but can be toxic to sesame in some cases. The method of incorporation is important in that pendimethalin is selective to sesame when the seed line is below the herbicide, and the herbicide does not move down to the root zone at the seedling stage. Have not done much research using new products that do not require PPI. In the US in Arizona, Howell et al. (1984) had the following results:

Treat PPI Herbicide Prowl (pendimethalin) Rate /ac 0.75 l Mid stunt no/no Mid stand OK/OK Broadleaf control no/no Grass control OK/OK Early vigor no/no

They concluded pendimethalin was unacceptable to use on sesame. In Australia in Queensland, Schrodter and Rawson (1984) evaluated PRE herbicides on sesame grown under weed free and weedy conditions in 3 experiments over two years. The following were the results of the first two experiments:

Herbicide Pendimethalin (PRE) c Weed free control 59 a 431 a Weedy control 52 ac 55d a 1000s/ha b Means not followed by a common letter differ significantly (P<0.05) c Experiment says PRE but probably PPI d Measured 29 days after planting Rate kg/ha 1.5 3.0 Number of plants a Yield kg/ha Number of plants 172 c 102 d 251 b 322 a Yield kg/ha 118 c 22 d 385 b 431 ab Plant height cm d 6d 4d 18 abc 20 a

The results of experiment 2 were as follows: · Pendimethalin reduced plant population, yield, and plant height. Plant maturity was delayed and was harvested 5 days later than the other treatments. · The reduction of population in the weed free control was probably a loss during the hand weeding operation.

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In India, Shukla (1984) found that Stomp (pendimethalin) was toxic to the crop. 1 l/ha of propanil gave effective control of weeds and resulted in higher yields. In Korea, Kim et al. (1986) conducted field trials to study the herbicide efficacy and phytotoxicity in crops grown under polyethylene film. Most effective overall weed control was obtained using 1.27 kg/ha pendimethalin, but it caused crop damage and yield reductions. In Egypt in Shandaweel, Ibrahim et al. (1988) studied the effect of 5 herbicides applied singly or in tank mixtures or hoeing on sesame crops infested with various weeds in 2 field trials in 198485. Treatments included 2.04 kg/ha pendimethalin, 1.2 kg/ha linuron, 0.96 kg/ha diuron, and 1.92 kg/ha prometryn applied PRE individually, or as tank mixtures of alachlor or pendimethalin with the other herbicides. Pendimethalin alone or with linuron or diuron gave excellent control of grass weeds, while linuron or diuron alone or mixed with pendimethalin effectively controlled broadleaved weeds. The best control of annual weeds and high seed yields and yield components resulted from treatment with pendimethalin alone or in tank mixtures with linuron or diuron. In Somalia, Malik and Ramzan (1992) conducted field studies during April-June and OctoberDecember 1989, to examine the efficacy and yield of PRE Stomp 330E (pendimethalin) at 3.7 l/ha as compared to hand weeding for the control of weeds infesting sesame. Greatest weed control was obtained using Stomp (86.04%), followed by hand weeding (84.97%). Stomp 330E treated plots gave a significantly higher seed yield (5.08 t/ha) compared to the untreated control (3.06 t/ha) and did not produce any phytotoxic effects. In Australia in the Northern Territories, a grower guide (Bennett 1998) states that grass weeds can be fairly easily controlled in a conventionally tilled sesame crop using PRE herbicides such as Stomp. In Brazil in Paraiba, Viera et al. (1998) tested the efficacy of mixtures of diuron (0.75, 1.0 and 1.25 kg/ha) with pendimethalin (1.25 kg/ha) as PRE herbicides. After 15 days, significantly greater phytotoxicity was observed following treatment with the highest dose of diuron plus pendimethalin (12.5%). Control ranged from 97 to 99% after 30 days and from 96 to 98% after 60 days. There were no significant differences for the height of the 1st fruiting branch, the number of fruits per plant, and the yield between the different treatments and mowing. In the US in South Texas, Grichar et al. (2001a) conducted field studies from 1994 through 1997 in Yoakum and in Uvalde in 1995 to evaluate soil-applied herbicides for weed control, sesame tolerance, and yield. There were four replications. The varieties used were Sesaco 11, 17, or 18. The plant height was taken from averaging 5 plants and taken 5-7 weeks after planting. The data is as follows:

Herbicide Pendimethalin Rate kg/ha 0.6 1.1 Applic PPI PPI 1994 5 WAP a 38.1 38.7 43.4 16.9 Sesame height (cm) 1995 1996 7 WAP 6 WAP 73.1 b 55.6 b b 32.8 51.8 131.3 43.4 31.0 11.6 1997 5 WAP 67.8 53.3 b 70.9 14.7

Check LSD (0.05) a WAP = weeks after planting b Significantly different from check

Pendimethalin reduced the height in all the trials and significantly in 4 of the 8. The sesame population was counted 4-6 weeks after planting. The data was as follows:

Plants/m of row

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Rate Herbicide kg/ha Applic Pendimethalin 0.6 PPI Pendimethalin 1.1 PPI Check LSD (0.05) a Significantly different from check

1995 6.0 a 8.5 a 70.3 23.5

1996 22.3 a 17.8 a 65.3 36.1

1997 10.2 a 1.8 a 67.5 18.8

Pendimethalin lowered the population significantly in all trials. The dinitroaniline herbicides were incorporated 2.5 cm deep which may have resulted in contact with the seed. The chemicals also may have moved down with moisture to be in contact. The weed control is based on 0 = not control and 100 = complete control. The weed control data was as follows:

Herbicide Pendimethalin Pendimethalin Check LSD (0.05) Rate kg/ha 0.6 1.1 Applic PPI PPI Broadleaf signalgrass 62 66 0 21 Brown-top panicum 99 100 0 10 Southern cragrass 98 99 0 18 Palmer amaranth 1994 1995 62 49 0 25 100 100 0 4

Pendimethalin provided good grass control but were erratic on broadleaf control as would be expected. The weed control data was as follows:

Rate Herbicide kg/ha Applic Pendimethalin 0.6 PPI Pendimethalin 1.1 PPI Check LSD (0.05) a Significantly different from check 1994 Yoakum 670 660 650 300 1995 Yoakum 870 310 1995 Uvalde 1240 1620 a 870 470 1996 Yoakum 980 a 810 480 450 1997 Yoakum 600 580 480 180

The data in the following table was converted to a percentage yield compared to the check, but the average did not include 1996 where all of the herbicides exceeded the yields of the check.

Rate 1994 Herbicide kg/ha Applic Yoakum Pendimethalin 0.6 PPI 103 Pendimethalin 1.1 PPI 102 a Significantly different from check 1995 Yoakum 1995 Uvalde 143 186 a 1996 Yoakum 204 a 169 1997 Yoakum 125 121 Average 124 136

By looking at the data in this way, it goes back to what Grichar said in the beginning that sesame with few weeds + some herbicide damage to the sesame is better than a lot of weeds + no damage to the sesame. Sesame has the ability to compensate for low stands by setting branches that load up with capsules. They concluded that pendimethalin is a good option for weed control but crop safety is a concern if the herbicide is incorporated too deep in a shallow planted crop. In India in Haryana, Punia et al. (2001) conducted an experiment on sandy loam soil during kharif 1999 and 2000, to investigate the efficacy of herbicides against weeds in sesame (cv. HY-1). Treatments included pendimethalin at 1.0, 1.25 and 1.5 kg/ha PRE and integration of with one hoeing at 4 weeks after sowing (WAS). On an average, season long weed competition caused 61% reduction in seed yield. Two hoeings at 3 and 6 WAS, integration of either fluchloralin, pendimethalin or trifluralin at 1.0 kg/ha with one hoeing at 4 WAS were significantly better in terms of weed control efficiency and seed yield compared to one hoeing at 4 WAS or herbicides used alone. In India in Rajasthan, Dungarwal et al. (2003) conducted a field experiment during the kharif seasons of 1997 and 1998 to evaluate the relative efficacy of pendimethalin applied alone or in

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combination with one hoeing at four weeks after sowing ( WAS) to control weeds in sesame (cv. TC 25). On average, season-long weed competition caused 50% reduction in seed yield. Integration of pendimethalin 1.0 kg/ha or at 2.0 kg/ha with one hoeing at 4 WAS was more effective when assessed in terms of weed control efficiency and seed yield compared to their single application. There were other more effective treatments. In Australia in the Northern Territories, Bennett (2003/2007, pers. commun.) stated, "We have no approved herbicides for sesame and need `minor crop' usage approval from the relevant authority. I like Stomp because it gives us protection against pigweed, which is a big bonus." In India in Rajasthan, Chandawat et al. (2004) conducted a field experiment to look at the efficacy of hand weeding 20 and/or 30 days after sowing (DAS) and 0.5 kg/ha pendimethalin applied alone or in combination with hand weeding 30 DAS. Weed control efficiency was highest (88%) with the PRE 1.5 kg/ha alachlor and 0.5 kg/ha pendimethalin in combination with hand weeding 30 DAS. Plant height was highest with the application of alachlor in combination with hand weeding. Application of 2 kg/ha alachlor in combination with hand weeding resulted in the highest number of primary branches per plant (45), pooled seed yield (713 kg/ha), net returns (10736 kg/ha), and benefit cost ratio (2.17). In India in Rajasthan, Yadav (2004) conducted a field experiment during the 1998 and 1999 kharif seasons on sesame (cv. RT-46) to determine a suitable integrated method for weed control. The treatments comprised: weedy control; one hand-weeding (HW) at 20 days after sowing (DAS); 2 HW at 20 and 40 DAS; PRE of 0.75 kg pendimethalin/ha; PRE of 0.5 kg/ha pendimethalin + HW at 40 DAS; and PRE of 0.75 kg/ha pendimethalin + HW at 40 DAS. There were other better treatments. In Pakistan, a grower guide (Panhwar 2005) recommends pendimethalin 1.0 kg/ha. In India in Tamil Nadu, Gnanavel and Anbhazhagan (2006) conducted a field experiment in summer 2002 to evaluate the efficacy of different PRE herbicides and herbicide along with hand weeding (HW) in controlling weeds in irrigated sesame cv. TMV 5. The treatments included 1.5 kg/ha pendimethalin and 1.0kg/ha pendimethalin + HW at 30 DAS. The application of 0.15 kg/ha oxyflourfen with one HW at 30 DAS was significantly better in terms of weed control index (92.7%) and seed yield (0.92 t/ha). In Pakistan, a grower guide (Anon 2007b) states the PRE herbicide Stomp 330 E at 1.48 ai kg/ha can be used before germination and is very effective in controlling wide range of grasses and broad leaf weeds. In Thailand, W. Wongyai (2007, pers. commun.) stated that some farmers apply Stomp (pendimethalin) for post-emergence, and she has used it in her nurseries for grass control. In Argentina in Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3 replications. There were 3 rains before emergence. The PRE test populations and weed control are as follows:

Weed control a 19 DDA b Herbicide Herbadox Active ingredient Pendimethalin c Rate/ha 2.5 l Stand 1.1 Ama 85

a

30 DDA

a

Rha 55

Ama 90

Rha 85

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Weed control a 19 DDA b Herbicide

a a

30 DDA

Active ingredient Rate/ha Stand Ama Rha Ama Rha Clean check 4.1 100 100 100 100 Weedy check 3.2 0 0 0 0 a Weed control with 0 = no control and 100 = complete control. Ama = Amaranthus quitensis and Rha = Raphanus sativus b DDA = days after application c Used the variants that do not require PPI.

There were four ratings done 19, 30, 60, and 88 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight of capsules in the center of the capsule zone. The number of seeds were counted and the seed weight per capsule (SWC) and was taken. The PRE data was as follows:

19 DDA Pendimethalin 3 Clean check 83 Weedy check 77 a DDA = days after application Active ingredient 30 DDA 12 87 77 60 DDA 47 88 78 88 DDA 50 82 72 Yield (g/m) 47.5 abcd 59.9 de 53.8 bcde W100 (g) 0.274 0.284 0.297 Sd/cap 68 71 69 SWC (g) 0.186 0.202 0.205

The pendimethalin reduced the yield substantially and did not control the weeds as well as other herbicides. In the US, the first author has made the following observations: · In Texas there are farmers that swear by trifluralin and neighbors that swear by pendimethalin. In planting nurseries with pendimethalin, it was used similarly to trifluralin in terms of dose and farming practices. The author has less experience with pendimethalin, but it was used when planting nurseries with farmers that use pendimethalin. · In the first year of planting, a full cotton rate of trifluralin was used, and there was enough of a stand reduction that a half rate was tried successfully. From that point forward, the pendimethalin rate was also cut in half. · The practice in the nurseries was to pre-irrigate, apply the pendimethalin at half cotton rate, incorporate it with a harrow, and plant. The pendimethalin did a good job controlling grasses and pigweed. · In some years in pulling up plants, there was some root pruning, but the plants still matured and looked normal. There was never an attempt to see if the pendimethalin had lowered the yield. In the yield sampling in the breeding program, the averages changed from year to year, but the changes could always be correlated to irrigations, fertility, and weather. There was never any reason to suspect that the pendimethalin affected the yield in a negative way, but it did affect the yield in a positive way by controlling weeds. · Starting back in 1987 there has been sesame planted after hailed out cotton. Pendimethalin had been applied prior to planting with different practices ­ some apply it in February/March and others apply it closer to the planting of cotton that ranges from late April to early June. With US insurance policies if there is a hail out prior to a certain date (the date varies with the area), then cotton has to be replanted, but after that any crop can be planted. Most of the sesame after hailed out cotton has occurred in the mid June to early July time-frame. There has never been a loss of a sesame stand after failed out cotton due to pendimethalin. It is not known if there is no effect because the pendimethalin has been diluted through rains into different ranges of soil or if the pendimethalin loses its potency over time.

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· In using pendimethalin it is critical to place the seed in the moisture below the hot zone of the pendimethalin. Dry soil with pendimethalin has been pulled over the seed line without an effect. There have been problems when there is a rain after the pendimethalin has been applied/incorporated and before the planting. In these cases, the seed is placed in the hot zone, and the stand can be damaged or even lost. · In cold weather, the sesame plants take longer to germinate and grow even more slowly. Pendimethalin appears to damage the plants more when it is colder than when it is warmer and the sesame germinates and grows faster. · As with trifluralin, in most cases pendimethalin works, but there have been fields that were completely lost because the pendimethalin reduced the stands substantially. · As more and more farmers move to no-till practices, pendimethalin will not be as good an option since it has to be incorporated or it will lose its effectiveness. With products such as Prowl H2O, the problem may be solver; however, there are mixed results to date among farmers. POST OTT summary: No known research, but some farmers apply it to provide residual control of grasses. In Thailand, W. Wongyai (2007, pers. commun.) stated that some farmers apply Stomp (pendimethalin) POST. In her nurseries she has applied it POST for grass control. POST DIR summary: No known research. Pendimethalin characteristics: (Anon 1994, 1998) · Other crop uses: Has been used as PPI, PRE, and early POST. It controls primarily grass weeds, barnyardgrass, crabgrass, Panicum, foxtail, goosegrass, seedling johnsongrass, signalgrass, and shattercane. There is some control of lambsquarters, redroot pigweed, and velvetleaf. It can be applied in liquid fertilizer, impregnated on dry bulk fertilizer, or through chemigation systems. · Description: Crystalline orange-yellow solid with faint nutty odor. · Symptomology: Highly susceptible annual grasses and broadleaves fail to emerge. Coleoptile growth in grasses is inhibited. Emerged grass shoots are deformed. Stems of broadleaves can become brittle at the soil line and hypocotyls may swell. The most easily recognized system is root growth inhibition, especially in lateral (secondary) roots. Root tips become thickened and stubby. · Absorption/translocation: Soil-applied it is absorbed by roots and coleoptiles. Translocation is not important since most of the damage is done on roots and coleoptile. · Mechanism of action: It affects the mitosis of cells at the end of the roots. · Sorption: Strongly adsorbed by clay and OM. · Transformation: - Photodegradation: Half-life is 7 days in water at 25°C in full sunlight. - Other degradation: Rapid degradation under anaerobic conditions. Aerobic biological degradation is slow. · Persistence: Typical half-life in the field is 44 days, but varied with temperature and moisture. Incorporation slows dissipation. · Volatilization: Is moderately volatile. Slight losses can occur in high temperature and wind. Mechanical incorporation within 7 days after application prevents appreciable losses. · Mobility: Immobile, strongly bound to OM and clay. · Miscellaneous information:

Common name Trade name Date Avg rate (lbs/ac) LD50 rat (mg/kg)

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Pendimethalin Prowl 1976 1.25 Current sample of label: http://www.cdms.net/manuf/mprod.asp?mp=16&ms=2273

2,679

Using the sample label above for Prowl H2O, there are rotational restrictions from immediate to 12 months depending on the crop and the amount of the herbicide used. The following are the restrictions for the common crops in the sesame growing areas in the US as of 24 July 07, but refer to the current label for current restrictions. Most crops may be rotated, but the label should be consulted because of different rates, tank mixes, and environments. There are some grazing restrictions.

PERFLUIDONE (Destun)

Out of production in US

PRE summary: Selective to sesame but poor weed control. In the US, in California, St Andre (1973) conducted PPI trials under furrow irrigation, planted 15 May. Variety was 247 (nonshattering). Evaluated 14 Jun. Note that the stands are much lower than the other St Andre testing. Nonshattering (indehiscent) lines have much less vigor than semi-shattering or shattering lines.

Stand count a Herbicide Rate Sesame Sesame Mustard Japanese Pigweed lb/ac vigorb millet Destun (perfluidone) 2.0 8.0 14.2 15.0 20.2 17 4.0 9.3 12.0 8.7 7.0 14 Untreated --10 12.2 7.5 5.5 23 a Stand count values represent the average number of plants in 8 feet of row in 4 replications except for the pigweed which was only present in the 3rd replication. b Vigor evaluation is based on a 0-10 scale with 0 = very poor vigor and 10 = vigorous growing plants.

Perfluidone had little effect on the sesame stand or vigor, but it did very poorly in control of all of the weeds. POST summary: No known research.

PHENMEDIPHAM (Betanal)

PRE summary: No known research. POST OTT summary: Toxic to sesame. In Bulgaria, Lyubenon and Kostadinon (1970) tried Betanal (phenmedipham) as a POST herbicide and found it toxic to sesame. POST DIR summary: No known research.

PIRAFLUFEN ETHYL (Ecopart)

PRE summary: No known research POST OTT summary: Somewhat selective to sesame with less yield than the checks.

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In Argentina in Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3 replications. There were 3 rains before emergence. The POST OTT herbicides were applied 19 days after planting. The weed control data was taken 13 days after application and was as follows:

Herbicide Ecopart Active ingredient Rate/ha Ama a Piraflufen ethyl 100 cc 10 Weed-free check 100 Weedy check 0 Weed control with 0 = no control and 100 = complete control. Rha = Raphanus sativus Rha a 100 100 0 Ama = Amaranthus quitensis and

a

There were three ratings done 13, 43, and 70 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight from capsules in the center of the capsule zone. The number of seeds were counted and the seed weight per capsule (SWC) and was taken. The POST OTT data was as follows:

13 43 DDAa DDA Piraflufen ethyl 57 88 Weed-free check 81 83 Weedy check 75 71 a DDA = days after application Active ingredient 70 DDA 77 78 65 Yieldg (g/m) 41.0 ab 48.4 ab 50.7 ab W100 (g) 0.303 0.300 0.300 Sd/cap 69.5 74.1 62.8 SWC (g) 0.211 0.222 0.188

The piraflufen ethyl did not have good weed control on the Amaranthus, but it must have set it back because there were few weeds at the end under the canopy. There was a lower yield at the end. POST DIR summary: No known research

PROATRYNE

PRE summary: Somewhat selective to sesame and good weed control, but there were better treatments. In Ethiopia, Brar (1979) cited Moore (1974) who studied 11 herbicides over two years and had the following results: Proatryne gave persistent weed control with negligible crop damage at 1.0 and 1.2 kg/ha. However, there were better treatments. POST summary: No known research.

PROFLURALIN (Pregard)

PRE summary: Somewhat selective to sesame and good weed control, but there were better treatments. In Bulgaria, Georgiev (1980) concluded that on the basis of trials at Sadovo between 1974 and 1979, suitable herbicides for weed control in sesame included: Agriflan Pregard (profluralin) at 2

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l/ha applied PPI to a depth of 8 to 10 cm. The quality and fat content of sesame seeds were not adversely affected by these treatments. There were other better treatments. POST summary: No known research.

PROMETRYN (Caparol, Gesagard, Suprend)

Sesame use: Potential use as POST DIR and may provide residual control. PRE summary: Toxic to sesame in most conditions with severe stand reduction. Has good weed control when the hot zone is cleared from the seed line so that the sesame can emerge. In Ethiopia, Moore (1973a, 1974) evaluated herbicides for use in sesame grown on a dark brown sandy clay loam under irrigation at Melka Werer. Prometryn applied PRE gave the best overall results. At 1 kg/ha, it controlled all weeds present except Cyperus spp. and Lactuca taraxifolia and persisted for 54 days. At 1.85 kg/ha persistence was extended to 105 days but some crop damage occurred. It gave seed yields up to 0.57 t/ha, but hand weeding 2 or 3 times gave yields 0.52-0.85 t/ha. In Ethiopia, Moore (1973b, 1974) carried out a trial in the higher rainfall area at Setit Humera where irrigation was not necessary. Prometryn at 2.2 kg/ha completely eliminated the crop (in contrast to the result obtained at Melka Werer) suggesting that this herbicide is safe only under irrigation. There were other better treatments. In the US in Arizona, Howell et al. (1984) had the following results:

Treat PPI PPI PPI PRE PPI PRE Herbicide Treflan (trifluralin) + Caparol (prometryn) Treflan (trifluralin) + Caparol (prometryn) Caparol (prometryn) Caparol (prometryn) Rate /ac 0.75 l 0.75 l 0.75 l 0.75 l 1l 1l Mid stunt OK/OK no/no OK/OK no/no Mid stand OK/OK no/no OK/OK no/no Broadleaf control OK/OK OK/OK OK/OK OK/OK Grass control OK/OK OK/OK no/no no/no Early vigor OK/OK no/no OK/OK no/no

They concluded that PPI prometryn was good, but that PRE prometryn was very poor. The PPI trifluralin/PPI prometryn was only one of three treatments that was OK across the board. In Korea, Kim et al. (1986) conducted field trials to study the herbicide efficacy and phytotoxicity in crops grown under polyethylene film. Most effective overall weed control was obtained using 0.12 kg/ha Codal (metolachlor + prometryn), but it caused crop damage and yield reductions. 3 l/ha napropamide or 1.5 l/ha alachlor gave sesame yields equivalent to that obtained with manual weed control. In Egypt in Shandaweel, Ibrahim et al. (1988) studied the effect of 5 herbicides applied singly or in tank mixtures or hoeing on sesame crops infested with various weeds in 2 field trials in 198485. Treatments included 1.92 kg/ha prometryn applied PRE individually, or as tank mixtures of alachlor or pendimethalin. There were other better treatments In Australia in South Burnett, a grower guide (Sapin et al. 2000) states, "Sesame will not tolerate Caparol (prometryn)."

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In the US in South Texas, Grichar et al. (2001a) conducted field studies from 1994 through 1997 in Yoakum and in Uvalde in 1995 to evaluate soil-applied herbicides for weed control, sesame tolerance, and yield. There were four replications. The varieties used were Sesaco 11, 17, or 18. The plant height was taken from averaging 5 plants and taken 5-7 weeks after planting. The data is as follows:

Herbicide Prometryn Rate kg/ha 0.4 1.1 Applic PRE PRE 1994 5 WAP a 43.4 16.9 Sesame height (cm) 1995 1996 7 WAP 6 WAP 120.4 50.3 109.2 47.8 131.3 43.4 31.0 11.6 1997 5 WAP 44.7 b 13.7 b 70.9 14.7

Check LSD (0.05) a WAP = weeks after planting b Significantly different from check

Prometryn significantly decreased height in only one year. The sesame population was counted 4-6 weeks after planting. The data was as follows:

Plants/m of row Herbicide Applic Prometryn PRE Prometryn PRE Check LSD (0.05) a Significantly different from check Rate kg/ha 0.4 1.1 1995 24.0 a 8.5 a 70.3 23.5 1996 85.5 34.8 65.3 36.1 1997 14.4 a 1.5 a 67.5 18.8

Prometryn lowered the populations significantly except for 1996. The weed control is based on 0 = not control and 100 = complete control. The weed control data was as follows:

Herbicide Prometryn Prometryn Check LSD (0.05) Rate kg/ha 0.4 1.1 Applic PRE PRE Broadleaf signalgrass 0 21 Brown-top panicum 65 90 0 10 Southern cragrass 95 88 0 18 Palmer amaranth 1994 1995 0 25 97 100 0 4

Prometryn was not tested in the worst year for weeds 1994, but did well in the other years. The weed control data was as follows:

Rate Herbicide kg/ha Applic Prometryn 0.4 PRE Prometryn 1.1 PRE Check LSD (0.05) a Significantly different from check 1994 Yoakum 650 300 1995 Yoakum 650 1160 870 310 1995 Uvalde 110 a 70 a 870 470 1996 Yoakum 570 620 480 450 1997 Yoakum 540 400 480 180

The data in the following table was converted to a percentage yield compared to the check, but the average did not include 1996 where all of the herbicides exceeded the yields of the check.

Rate 1994 Herbicide kg/ha Applic Yoakum Prometryn 0.4 PRE Prometryn 1.1 PRE a Significantly different from check 1995 Yoakum 75 133 1995 Uvalde 13 a 8a 1996 Yoakum 119 129 1997 Yoakum 113 83 Average 67 75

Prometryn was the only herbicide that had significant lower average yields.

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In the US in Texas, Grichar and Dotray (2007) conducted PRE and POST OTT studies in two locations (Yoakum and Lubbock) in 2004 and 2005. The data from the PRE tests was as follows:

Stand reduction b Injury b Yield c Rate Weed control 2004 2005 2004 2005 2005 Treat kg/ha AMATU BRAPP Lub Yoa Yoa Lub Yoa kg/ha Check 0 0 0 0 0 0 0 380 Prometryn 1.12 89 52 43 58 27 53 14 418 LSD (0.10) 15 28 40 25 29 29 18 217 a Bayer code for weeds: AMATU (Amaranthus tuberculatus) tall waterhemp, BRAPP (Brachiaria platyphylla) broadleaf signalgrass b Stand reduction and injury index: 0 = no stand reduction or sesame injury; 100 = complete stand reduction or plant death c Weed control and sesame yield taken at the Yoakum location only

a, c

They concluded that prometryn damaged the sesame, but because of weed control increased the yield. In Argentina in Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3 replications. There were 3 rains before emergence. The PRE test populations and weed control are as follows:

Weed control a 19 DDA b Herbicide Gesagard

a a

30 DDA

Active ingredient Rate/ha Stand Ama Rha Ama Rha Prometryn 1.5 l 0.2 100 90 100 90 Clean check 4.1 100 100 100 100 Weedy check 3.2 0 0 0 0 a Weed control with 0 = no control and 100 = complete control. Ama = Amaranthus quitensis and Rha = Raphanus sativus b DDA = days after application

There were four ratings done 19, 30, 60, and 88 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight of capsules in the center of the capsule zone. The number of seeds were counted and the seed weight per capsule (SWC) and was taken. The PRE data was as follows:

19 DDA Prometryn 0 Clean check 83 Weedy check 77 a DDA = days after application Active ingredient 30 DDA 3 87 77 60 DDA 0 88 78 88 DDA 5 82 72 Yield (g/m) 59.9 de 53.8 bcde W100 (g) 0.284 0.297 Sd/cap 71 69 SWC (g) 0.202 0.205

Pormetryn prevented germination of sesame, but it did provide good weed control. In the US, the first author has made the following observations: · In Arizona the prometryn initially looked very promising for use in sesame. However, in one year there was zero stand of sesame on fields with prometryn. In analyzing the differences, in the initial years the double disc opener planters had packing wheels that closed the seed line. In some fields, the closers left a gap and the seed line dried out. Chains were attached to the back of the planter boxes to pull dry dirt over the seed line and cover the gap, and suddenly there was no stand with prometryn. Essentially, in the early years the planter was peeling back the hot zone of prometryn over the seed line and not bringing it back over the line. With the chains, the hot zone was brought back over the top. Lifting of chains on every other planter box on the

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tool bar confirmed the theory in that the rows without the chains had perfect stands except where the soil dried out, and there was no stand where the chains pulled the soil over the seed line. · The only hailed out cotton fields that have had poor stands of sesame have been those with prometryn. On the other hand there have been fields with prometryn that had good stands. It is not known what was different, but researchers have theorized that prometryn does not move as much with the rain as other herbicides and the lack of stands may be related to little rainfall between application and sesame planting. POST OTT summary: Toxic to sesame ranging from complete kill to reduction of yield and some injury. Too risky. In Australia in Queensland, Schrodter and Rawson (1984) evaluated PRE and POST herbicides on sesame grown under weed free and weedy conditions in Lockyer Valley in 4 experiments over two years. The variety Palmetto was used. The first two experiments were with PRE herbicides and the last two included POST herbicides. The POST applications were done 21 days after planting while the plants were in the third true leaf stage. The second POST experiment tried a few other POST herbicides with the following results

Herbicide Prormetryn Weed free control Weedy control a 1000s/ha b Scale 0-5 with 0 = majority of plants dead, 5 = all plants healthy, uniform growth. Taken 29 days after planting. c Means not followed by a common letter differ significantly (P<0.05) Rate kg/ha 2.0 Number of plants a 0c 312 a 290 a Yield kg/ha 0 937 ab 492 c Plant vigour rating b 0 5.0 a 5.0 a

The results of the experiment were as follows: Prometryn destroyed the crop. In the US in South Texas, Grichar and Langham (2003) conducted a POST OTT test. A 5 ft swath of herbicides was sprayed across three rows of five lines leaving 15 ft of each row untouched to allow a direct within row comparison of the effects of the treatments. The herbicides were sprayed over the top in the juvenile stage when the plants were about 18" tall. There was a dual purpose: (1) find herbicides that were selective to sesame and (2) find herbicides that would control volunteer sesame in other crops. In this test, there were no weeds since the main thrust of the study was to look at the effects of the herbicide on the sesame. There were no replications in that the idea was to take the better lines and test them in Grichar et al. (2007). At the end of the ripening phase, the plots were evaluated in terms of percentage production compared to the untouched line in the same row.

Treatment Prometryn Rate 0.5x 1.0x Average S26 60 40 37 S27 60 50 49 S28 60 40 37 S29 60 40 48 132 70 40 31 Average 62 42 40

The half rate of prometryn was better than the average, but not good enough to use as a POST OTT. In the US, Grichar and Dotray (2007) conducted POST OTT studies in two locations in Texas (Yoakum and Lubbock) in 2004 and 2005. The herbicides were applied in the pre-reproductive stage when the plants were about 60 cm tall. The Lubbock trials were virtually weed free while there were weeds in the Yoakum trials. The data from the tests was as follows:

Sesame injury (%) a Yield (kg/ha)

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Rate 2004 2005 2004 2005 Treatment b kg/ha Lub Yoa Lub Yoa Lub Lub Yoa Check 0 0 0 0 125 1,008 314 Prometryn 1.12 48 30 16 7 27 835 476 LSD (0.10) 11 36 20 105 226 a Injury index: 0 = no sesame injury; 100 = complete plant death. Ratings taken 6-8 wks after herbicide application b All herbicides included a non-ionic surfactant added at 0.25% v/v or a crop oil concentrate added at 1 qt/ac.

Their conclusions were as follows: · In Lubbock where there were no weeds, the treatment reduced the yield, while in Yoakum, the treatment by controlling the weeds had a higher yield than the control. · The treatment caused intermediate injury to the sesame. In Argentina in Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3 replications. There were 3 rains before emergence. The POST OTT herbicides were applied 19 days after planting. The weed control data was taken 13 days after application and was as follows:

Herbicide Gesagard Active ingredient Rate/ha Ama a Prometryn 2000 cc 100 Weed-free check 100 Weedy check 0 Weed control with 0 = no control and 100 = complete control. Rha = Raphanus sativus Rha a 100 100 0 Ama = Amaranthus quitensis and

a

There were three ratings done 13, 43, and 70 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight from capsules in the center of the capsule zone. The number of seeds were counted and the seed weight per capsule (SWC) and was taken. The POST OTT data was as follows:

13 43 DDAa DDA Prometryn 0 0 Weed-free check 81 83 Weedy check 75 71 a DDA = days after application Active ingredient 70 DDA 2 78 65 Yieldg (g/m) 48.4 ab 50.7 ab W100 (g) 0.300 0.300 Sd/cap SWC (g) 0.222 0.188

74.1 62.8

The prometryn completely destroyed the sesame. POST DIR summary: By itself there was an increase in yield in one location and a slight reduction in another location. Provides residual control. Needs more research before using in farmer fields. In further testing in 2007. In Texas, Grichar et al. (2006) experimented with POST DIR treatments in Uvalde and Lubbock in 2006. The experiment is being repeated in 2007. The variety used was Sesaco 29 planted 25 May in Uvalde and 20 June in Lubbock. The herbicides were applied 2" and 6" from the ground on both sides of the stem when the plants were about 18" tall in the juvenile stage. The treatments were replicated 3 times. In Uvalde the experiment was under a lateral pivot with extreme variation. As a result the yield data was taken by cutting a sample within the treatment and a sample in the adjacent untreated row. The yield below is a percent of the treated row divided by the untreated row. The Lubbock experiment was rainfed with some variation between

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rows, and the percentage yield below represents the treatment plot divided by the check plot. In both locations the day after planting, a PRE treatment of metolachlor plus glyphosate was sprayed over the fields. There was no weed pressure in either location since the purpose of the initial experiment was to find herbicides that would be selective to sesame.

Active ingredient Prometryn + Glyphosate Prometryn Rate lbs/ ac 1.0 0.75 1.0 Height of applic 2" 6" 2" 6" Stunting Lub 0 3 0 5 Uva Yield % of check Lub Uva 75 110 65 85 85 112 94 114

Prometryn shows some promise by itself, but with glyphosate reduced the yields substantially in Lubbock. In the US, the first author has made the following observations: · Prometryn has been used as a POST DIR when the sesame is in the early reproductive phase while it is still possible to get ground rigs into the fields. The prometryn has controlled morningglory and smellmelon (Cucumis melo). The leaves at the bottom of the sesame were affected, but the plants did not die, and there was no effect on the upper canopy. There was no side by side comparison with a control to see the effects on yields, but visually the crop terminated normally. Prometryn characteristics: (Anon 1994, 1998) · Other crop uses: Used as a PPI, PRE, POST OTT, and POST DIR. Weeds controlled include ground cherry, lambsquarters, morningglory spp., pigweed spp., prickly sida, foxtail spp., goosegrass, and others · Description: White, crystalline solid · Symptomology: Begins with interveinal chlorosis of the leaves and yellowing of leaf margin, followed in susceptible plants by further chlorosis and necrosis. Browning of leaf tips can occur. Root growth is not affected. · Absorption/translocation: Readily absorbed through roots and translocated to the shoots via the apoplast (including the xylem). Readily absorbed into leaves from POST applications with essentially no basipetal translocation out of the treated leaf. · Mechanism of action: Inhibits photosynthesis. · Sorption: Moderately adsorbed to soils. · Transformation: - Photodegradation: Stable on sandy loam soil at 15-28°C with natural light, negligible contribution to dissipation in the field - Other degradation: Half-life was 261 days for aerobic microbial metabolism. Prometryn applied under anaerobic conditions is stable at 25°C. · Persistence: Average field half-life is 60 days. · Mobility: No quantifiable prometryn residues were found below 30 cm (12"). · Volatilization: Low volatization losses. · Miscellaneous information:

Common name Trade name Date Avg rate (lbs/ac) LD50 rat (mg/kg) Prometryn Caparol 1969 1.975 3,750 Current sample of label: http://www.syngentacropprotection-us.com/pdf/labels/SCP620AL6R1203.pdf

Using the sample label above for Caparol 4L, there are rotational restrictions from immediate to the following crop season depending on the crop, tank mixtures with other herbicides, and the

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amount of the herbicide used. Refer to the current label for current restrictions. Do not feed treated forage to livestock or graze in treated areas.

PRONAMIDE (Kerb)

PRE summary: Toxic to sesame with severe reduction in stands and very bad injury. In the US in California, St Andre (1970a) conducted PPI trials under furrow irrigation, planted 14 May. Variety was 215 (semi-shattering). Evaluated 2 Jun.

Herbicide Rate Sesame Grass lb/ac Kerb (pronamide) 1.0 1.3 0 0 0 2.0 0.6 0 0 0 Untreated --96.0 6.6 1.3 58.3 a Stand count values represent the average number of plants in 8 feet of row b Ratings based on 0-10 scale. 0 = no control or injury. 10 = perfect control or very severe injury. Injury rating reflects retardation and vigor in the growth of sesame. Stand count a Pigweed Mustard Visual rating b Weed Sesame control injury 10 9.6 10 10 0 0

Kerb reduced sesame stands substantially, had very bad sesame injury, but had excellent weed control In the US in California, Fischer (1971) summarized the work that had been done between 1967 and 1970 in the San Joaquin valley to include the results of St Andre (1969, 1970a, and 1970b). In that area the concept was to grow sesame double cropped after barley or other cereals, and thus the emphasis was on controlling volunteer grasses. He summarized the results for the years as follows:

Trade name Kerb Active ingredient Pronamide Lbs/ac evaluated 1.0/2.0 Sesame tolerance Poor Barley control Good

POST summary: No known research.

PROPACHLOR (Ramrod)

PRE summary: Selective to sesame with good weed control, but limited research. In Bulgaria, Lyubenov and Kostadinov (1970) conducted trials in 1969 with sesame sown on chernozem smolnitsa soil on 29 May. PRE application mixtures of 4 kg/ha Patoran (metobromuron [OP]) and 5 kg/ha Ramrod (propachlor) gave effective control of weeds and increased seed yields and seed oil content. POST summary: No known research.

PROPANIL (Stam-F34)

PRE summary: Somewhat selective to sesame with effective weed control, but limited research.

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In India, Shukla (1984) found that a spray of 1 l/ha of propanil (Stam-F34) before sowing sesame gave effective control of weeds and resulted in seed yields of 127.5 kg/ha, compared with 132.5 kg on hand weeded plots and 72.5 kg without weed control. POST summary: No known research.

PROPAZINE (Milogard, Milocep, Milo Pro)

PRE summary: No known research. In 2007 testing. POST OTT summary: No known research. In 2007 testing. POST DIR summary: No known research. In 2007 testing.

PROSULFURON (Exceed, Peak)

PRE summary: No known research, but mixed results in planting sesame after herbicide used in previous cereal crop. In the US, there are many wheat farmers that apply sulfuron products late in the wheat crop to control broadleaf weeds. There are been mixed results in planting sesame after these products. POST OTT summary: Toxic to sesame with substantial production reduction, but did not kill the sesame. In the US in South Texas, Grichar and Langham (2003) conducted a POST OTT test. A 5 ft swath of herbicides was sprayed across three rows of five lines leaving 15 ft of each row untouched to allow a direct within row comparison of the effects of the treatments. The herbicides were sprayed over the top in the juvenile stage when the plants were about 18" tall. There was a dual purpose: (1) find herbicides that were selective to sesame and (2) find herbicides that would control volunteer sesame in other crops. In this test, there were no weeds since the main thrust of the study was to look at the effects of the herbicide on the sesame. There were no replications in that the idea was to take the better lines and test them in Grichar et al. (2007). At the end of the ripening phase, the plots were evaluated in terms of percentage production compared to the untouched plants in the same row.

Treatment Prosulfuron (Exceed) Prosulfuron (Peak) Rate 0.5x 1.0x 0.5x 1.0x Average S26 40 30 40 30 37 S27 50 60 60 60 49 S28 50 50 30 30 37 S29 80 50 40 30 48 132 40 30 30 20 31 Average 52 44 40 34 40

Prosulfuron is a bit above average in production, but not good. There is a difference between the two trade name materials. POST DIR summary: No known research.

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PYRAFLUFEN ETHYL (ET)

PRE summary: No known research. POST OTT summary: Somewhat toxic to sesame with initial injury, but the plants recovered at the end. Mixed on weed control. In Argentina in Salta, Lanfranconi et al. (2007) are currently conducting PRE and POST experiments. Sesaco 26 was planted 6 Feb. There were 3 rains before emergence. The POST applications were made 21 days after planting. The preliminary results of the POST tests are as follows:

Weed control % a Injury % b Stand % c d Treatment Rate/ha Ama Rha 13 dda 30 dda 70 dda Pyraflufen ethyl 100 cc 10 100 53 85 77 Weed-free check 0 0 77 78 Weedy check 0 0 72 65 a Rating is based on 0= no control and 100 = 100% control. Ama = Amaranthus and Rha = Raphanus b Rating is based on 0= no injury and 100 = 100% injury c Rating is based on 0= no stand and 100 = 100% stand d dda = days after application

One further rating will be done once the leaves fall and yield samples will be taken from the good treatments. The pyraflufen ethyl had some weed control, damaged the sesame, but the sesame recovered at the end. POST DIR summary: Selective to sesame with no visual damage, but there are slight reductions in yield. Needs more research before using in farmer fields. In further testing in 2007. Grichar, Dotray, and Langham experimented with POST DIR treatments in Uvalde and Lubbock in 2006. The experiment is being repeated in 2007. The variety used was Sesaco 29 planted 25 May in Uvalde and 20 June in Lubbock. The herbicides were applied 2" and 6" from the ground on both sides of the stem when the plants were about 18" tall in the juvenile stage. The treatments were replicated 3 times. In Uvalde the experiment was under a lateral pivot with extreme variation. As a result the yield data was taken by cutting a sample within the treatment and a sample in the adjacent untreated row. The yield below is a percent of the treated row divided by the untreated row. The Lubbock experiment was rainfed with some variation between rows, and the percentage yield below represents the treatment plot divided by the check plot. In both locations the day after planting, a PRE treatment of metolachlor plus glyphosate was sprayed over the fields. There was no weed pressure in either location since the purpose of the initial experiment was to find herbicides that would be selective to sesame.

Active ingredient Pyraflufen-ethyl Rate lbs/ ac 0.016 Height of applic 2" 6" Stunting Lub 0 5 Uva Yield % of check Lub Uva 96 78 95 88

Pyraflufen-ethyl showed a minor reduction in yield in Lubbock, but had one of the lower yields in Uvalde. Harvest aid summary: Does not dry down the crop any faster than natural drydown.

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PYRIDATE (Lentagran, Tough)

PRE summary: No known research. POST OTT summary: Mixed results with toxic at high rates and somewhat selective at lower rates. Too risky to use. In the US in South Texas, Grichar et al. (2001b) conducted POST OTT studies in weed free areas at Yoakum and Uvalde from 1994 to 1997. The varieties used were Sesaco 11, 17, or 18. The herbicides were applied over the top 3-4 wk after planting in Yoakum and 6 wk after planting in Uvalde. Sesame was 30-48 cm in height at the time of application. Planting dates in Yoakum were 26 May 1994, 11 July 1995, 12 July 1996, and 1 July 1997. Planting date in Uvalde was 28 April 1995. Ratings of stunting (0= no stunting and 100 = total stunting) were done 3 weeks after herbicide application as shown below.

Rate (kg/ha) Check Pyridate LSD (0.05) 0.50 1.00 94 YOA 0 22 17 28 95 UVA 0 25 38 19 95 YOA 0 3 11 12 96 YOA 0 0 70 22 97 YOA 0 8 6 12

Pyridate was mixed on the amount of stunting with some severe and some almost none. The effects on plant height (cm) were as follows:

Rate (kg/ha) Check Pyridate LSD (0.05) 0.50 1.00 94 YOA 91 77 83 26 95 YOA 110 111 109 32 96 YOA 71 62 34 23 97 YOA 74 50 64 16

Pyridate was mixed on height reductions with some severe and others almost none. The yields (kg/ha) were as follows:

Rate (kg/ha) Check Pyridate LSD (0.05) 0.50 1.00 94 YOA 408 210 345 248 95 UVA 844 432 836 210 95 YOA 482 325 487 255 96 YOA 419 0 282 217 97 YOA 501 531 504 NS Avg 531 375 491 % check 71 92

Pyridate is one of the few herbicides where the higher rate helped the yields. However, the yields were still lower than the check. POST DIR summary: No known research.

PYRITHIOBAC (Staple)

PRE summary: Toxic to sesame with severe reduction in stands, yield, and considerable injury. In the US in Texas, Grichar and Dotray (2007) conducted PRE and POST OTT studies in two locations (Yoakum and Lubbock) in 2004 and 2005. The data from the PRE tests was as follows:

Rate Weed control

a, c

Stand reduction b 2004 2005

Injury b 2004 2005

Yield c 2005

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Treat kg/ha AMATU BRAPP Lub Yoa Yoa Lub Yoa kg/ha Check 0 0 0 0 0 0 0 380 Pyrithiobac 0.07 99 36 30 48 77 75 8 186 LSD (0.10) 15 28 40 25 29 29 18 217 a Bayer code for weeds: AMATU (Amaranthus tuberculatus) tall waterhemp, BRAPP (Brachiaria platyphylla) broadleaf signalgrass b Stand reduction and injury index: 0 = no stand reduction or sesame injury; 100 = complete stand reduction or plant death c Weed control and sesame yield taken at the Yoakum location only

They concluded that pyrithiobac is not a good PRE herbicide for sesame. In the US, the first author has made the following observations: · Cotton farmers are using more and more pyrithiobac. In 2003 about 400 ha of sesame were planted on hailed out fields that had used pyrithiobac with no sesame stand problems. However, the farmer tried 20 ha and waited until after emergence before planting the rest because of fears of problems. Pyrithiobac is very water soluble and in 2003 the hail was accompanied by a lot of rain. This herbicide might be a problem with less rainfall. POST OTT summary: Toxic to sesame with substantial injury and reduction in yield, but did not kill the sesame. In the US, Grichar and Dotray (2007) conducted POST OTT studies in two locations in Texas (Yoakum and Lubbock) in 2004 and 2005, but pyrithiobac was only tested in Yoakum. The herbicides were applied in the pre-reproductive stage when the plants were about 60 cm tall. There were weeds in the Yoakum trials. The data from the tests was as follows:

Sesame injury (%) a Yield (kg/ha) Rate 2004 2005 2004 2005 Treatment b kg/ha Lub Yoa Lub Yoa Lub Lub Yoa Check 0 0 0 0 125 1,008 314 Pyrithiobac 0.04 100 67 142 LSD (0.10) 11 36 20 105 226 a Injury index: 0 = no sesame injury; 100 = complete plant death. Ratings taken 6-8 wks after herbicide application b All herbicides included a non-ionic surfactant added at 0.25% v/v or a crop oil concentrate added at 1 qt/ac.

Their conclusions were as follows: · In Yoakum, the treatment was one of the few treatments that severely reduced the yield. · The treatment caused severe injury to the sesame. POST DIR summary: Toxic to sesame with severe stunting within two weeks of application and resulted in a substantial reduction in yield. In further testing in 2007. Grichar, Dotray, and Langham experimented with POST DIR treatments in Uvalde and Lubbock in 2006. The experiment is being repeated in 2007. The variety used was Sesaco 29 planted 25 May in Uvalde and 20 June in Lubbock. The herbicides were applied 2" and 6" from the ground on both sides of the stem when the plants were about 18" tall in the juvenile stage. The treatments were replicated 3 times. In Uvalde the experiment was under a lateral pivot with extreme variation. As a result the yield data was taken by cutting a sample within the treatment and a sample in the adjacent untreated row. The yield below is a percent of the treated row divided by the untreated row. The Lubbock experiment was rainfed with some variation between rows, and the percentage yield below represents the treatment plot divided by the check plot. In both locations the day after planting, a PRE treatment of metolachlor plus glyphosate was sprayed

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over the fields. There was no weed pressure in either location since the purpose of the initial experiment was to find herbicides that would be selective to sesame.

Active ingredient Pyrithiobac Rate lbs/ ac 0.063 Height of applic 2" 6" Stunting Lub 17 43 Uva Yield % of check Lub Uva 67 76 64 55

Pyrithiobac damaged the sesame more than any other treatment. The stunting was seen within a few days of spraying and although the plants survived the yields were reduced substantially. The good news is that pyrithiobac is used in cotton where there are occasional sesame volunteers and the pyrithiobac should be able to control the sesame.

RIMSULFURON (Matrix)

PRE summary: Selective to sesame, but limited research. Further testing is warranted. In the US in Texas, Grichar and Dotray (2007) conducted PRE and POST OTT studies in two locations (Yoakum and Lubbock) in 2004 and 2005. The data from the PRE tests was as follows:

Stand reduction b Injury b Yield c Rate Weed control 2004 2005 2004 2005 2005 Treat kg/ha AMATU BRAPP Lub Yoa Yoa Lub Yoa kg/ha Check 0 0 0 0 0 0 0 380 Rimsulfuron 0.03 94 67 5 23 1 297 LSD (0.10) 15 28 40 25 29 29 18 217 a Bayer code for weeds: AMATU (Amaranthus tuberculatus) tall waterhemp, BRAPP (Brachiaria platyphylla) broadleaf signalgrass b Stand reduction and injury index: 0 = no stand reduction or sesame injury; 100 = complete stand reduction or plant death c Weed control and sesame yield taken at the Yoakum location only

a, c

They concluded that rimsulfuron shows potential as a PRE herbicide for sesame. POST OTT summary: Toxic to sesame with substantial production reduction, but did not kill the sesame. In one test there was an increase in yield compared to a weedy check. In the US in South Texas, Grichar and Langham (2003) conducted a POST OTT test. A 5 ft swath of herbicides was sprayed across three rows of five lines leaving 15 ft of each row untouched to allow a direct within row comparison of the effects of the treatments. The herbicides were sprayed over the top in the juvenile stage when the plants were about 18" tall. There was a dual purpose: (1) find herbicides that were selective to sesame and (2) find herbicides that would control volunteer sesame in other crops. In this test, there were no weeds since the main thrust of the study was to look at the effects of the herbicide on the sesame. There were no replications in that the idea was to take the better lines and test them in Grichar et al. (2007). At the end of the ripening phase, the plots were evaluated in terms of percentage production compared to the untouched plants in the same row.

Treatment Rimsulfuron Rate 0.5x 1.0x Average S26 50 30 37 S27 70 40 49 S28 60 40 37 S29 50 40 48 132 50 20 31 Average 56 34 40

Rimsulfuron had a substantial reduction in production.

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In the US, Grichar and Dotray (2007) conducted POST OTT studies in two locations in Texas (Yoakum and Lubbock) in 2004 and 2005. The herbicides were applied in the pre-reproductive stage when the plants were about 60 cm tall. The Lubbock trials were virtually weed free while there were weeds in the Yoakum trials. The data from the tests was as follows:

Sesame injury (%) a Yield (kg/ha) Rate 2004 2005 2004 2005 Treatment b kg/ha Lub Yoa Lub Yoa Lub Lub Yoa Check 0 0 0 0 125 1,008 314 Rimsulfuron 0.03 99 78 63 28 0 347 485 LSD (0.10) 11 36 20 105 226 a Injury index: 0 = no sesame injury; 100 = complete plant death. Ratings taken 6-8 wks after herbicide application b All herbicides included a non-ionic surfactant added at 0.25% v/v or a crop oil concentrate added at 1 qt/ac.

Their conclusions were as follows: · In Lubbock where there were no weeds, the treatment severely reduced the yield, while in Yoakum, the treatment by controlling the weeds had a somewhat higher yield than the control. · The treatment caused severe injury to the sesame. POST DIR summary: No known research.

SESONE (Crag)

Out of production in US PRE summary: At low rates selective to sesame, and at higher rates toxic to sesame. In the US, Culp and McWhorter (1965) cited Tocquigny and Livingston (1953) that sesone was promising for use in sesame. Weiss (1971) adds that the sesone caused slight stunting. In India, Weiss (1971) cites Mani (1961) that sesone gave promising results for broadleaf weeds but not for perennial monocots. Rates of 1.4 and 2.8 kg/ha were applied and the highest yields were obtained with the 1.4 rate which was not significantly higher than the hand cleaned plots. The 2.8 rate was slightly phytotoxic and caused abnormal proliferation of the tap-root. POST summary: No known research.

SETHOXYDIM (Poast, Sertin)

Sesame use: Used in commercial fields as a POST. No label in US. PRE summary: No known research. POST OTT summary: Selective to sesame and good grass control. In Australia in South Burnett, a grower guide (Sapin et al. 2000) states that sesame is susceptible to, but will tolerate sethoxydim (Poast, Sertin) but it is not registered in Australia.

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In the US in South Texas, Grichar et al. (2001b) conducted POST OTT studies in weed free areas at Yoakum and Uvalde from 1994 to 1997. The varieties used were Sesaco 11, 17, or 18. The herbicides were applied over the top 3-4 wk after planting in Yoakum and 6 wk after planting in Uvalde. Sesame was 30-48 cm in height at the time of application. Planting dates in Yoakum were 26 May 1994, 11 July 1995, 12 July 1996, and 1 July 1997. Planting date in Uvalde was 28 April 1995. Ratings of stunting (0= no stunting and 100 = total stunting) were done 3 weeks after herbicide application as shown below.

Rate (kg/ha) Check Sethoxydim LSD (0.05) 0.21 94 YOA 0 0 28 94 YOA 91 105 26 94 YOA 408 704 248 95 UVA 0 0 19 95 YOA 110 126 32 95 UVA 844 849 210 95 YOA 0 0 12 96 YOA 71 68 23 95 YOA 482 754 255 96 YOA 0 0 22 97 YOA 74 75 16 96 YOA 419 381 217 97 YOA 501 621 NS Avg 531 662 % check 125 97 YOA 0 0 12

Sethoxydim did not show any stunting. The effects on plant height (cm) were as follows:

Rate (kg/ha) Check Sethoxydim LSD (0.05) 0.21

Sethoxydim did not reduce plant height. The yields (kg/ha) were as follows:

Rate (kg/ha) Check Sethoxydim LSD (0.05) 0.21

Sethoxydim did not reduce the yield and actually increased the yield by controlling the grasses. In Australia in the Northern Territories, Bennett (2003, 2007, pers. commun.): "We have no approved herbicides for sesame and need `minor crop' usage approval from the relevant authority. If grass weeds become a problem post emerge we use Sertin (sethoxydim) at recommended rates." In the US, the first author has made the following observations: · Sethoxydim has been applied in many stages and in many ways without any damage to the sesame. It has been applied as early as the seedling stage (first true leaf) through late drydown stage. It has been applied by back-pack, ground rig, and from the air. · The only problem with sethoxydim has been that it is not always effective against the johnsongrass if it gets too tall and is no longer growing. Although it is easy to kill johnsongrass from seeds, it is difficult to kill the rhizomes and that johnsongrass may emerge later in the season. POST DIR summary: No known research, but logically if the grass weeds are short, a POST DIR application would allow contact with the small weeds in the seed line which are protected by the sesame plants from an over the top application. Sethoxydim characteristics: (Anon 1994, 1998) · Other crop uses: Has been used as a POST to control annual and perennial grasses. An oil adjuvant or nonionic surfactant is required for maximum efficacy. · Description: Amber-colored, oily liquid, odorless. · Symptomology: Growth ceases soon after application with young and actively growing tissues affected first. Leaf chlorosis and eventually necrosis develop 1-3 weeks after application.

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·

· · · · · · ·

Older leaves often turn purple, orange, or red before becoming necrotic. With PRE applications, the primary root is inhibited and leaves do not emerge from coleoptile. Absorption/translocation: Rapidly absorbed into roots or leaves, particularly when applied with an adjuvant. It is rainfast by 1 hour after application, although reduced herbicide efficacy has been noted when rainfall occurs 2 hours after application. Sethoxydim is systemic and translocates both in the phloem and xylem, although primarily in the phloem. It accumulates in meristematic areas of shoots and roots but the rate of translocation out of treated leaves is low and the extent of translocation is limited. Mechanism of action: Inhibition of fatty acid synthesis prevents the building of new membranes required for cell growth. Sorption: Adsorption varies with OM content. Transformation: - Photodegradation: Photolysis is <1 hour in water, <4 hours in soil. - Other degradation: Microbially degraded. Persistence: Rapidly degraded with an average field half-life of 5 days. Mobility: Not available. Volatilization: Negligible losses. Miscellaneous information:

Common name Trade name Date Avg rate (lbs/ac) Sethoxydim Poast 1983 0.55 Current sample of label: http://www.greenbook.net/docs/LABEL/L26409.PDF LD50 rat (mg/kg) 2,676

Using the sample label above for Poast, there are rotational restrictions from immediate to 120 days depending on the crop and the amount of the herbicide used. Refer to the current label for current restrictions.

SIMAZINE (Princep)

PRE summary: Toxic to sesame with severe injury. In the US in Mississippi, Culp and McWhorter (1965) cited Culp and Holstun (1958) that sesame was severely injured by simazine at 2 and 4 lb/ac. POST summary: No known research.

SIRMATE

PRE summary: Was not as good as other treatments. In India at Sumerpur, Brar (1979) cited Anon (1977) that sirmate did not give as good a result as alachlor, and weeding was still more economical and effective in weed control. POST summary: No known research.

SULFENTRAZONE (Authority)

PRE summary: Toxic to sesame with close to zero stand.

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In Argentina in Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3 replications. There were 3 rains before emergence. The PRE test populations and weed control are as follows:

Weed control a 19 DDA b Herbicide Authority

a a

30 DDA

Active ingredient Rate/ha Stand Ama Rha Ama Rha Sulfentrazone 500 cc 0 100 90 100 99 Clean check 4.1 100 100 100 100 Weedy check 3.2 0 0 0 0 a Weed control with 0 = no control and 100 = complete control. Ama = Amaranthus quitensis and Rha = Raphanus sativus b DDA = days after application

There were four ratings done 19, 30, 60, and 88 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight of capsules in the center of the capsule zone. The number of seeds were counted and the seed weight per capsule (SWC) and was taken. The PRE data was as follows:

19 DDA Surfrentazone 0 Clean check 83 Weedy check 77 a DDA = days after application Active ingredient 30 DDA 0 87 77 60 DDA 0 88 78 88 DDA 5 82 72 Yield (g/m) 59.9 de 53.8 bcde W100 (g) 0.284 0.297 Sd/cap 71 69 SWC (g) 0.202 0.205

Sulfentrazone had excellent weed and sesame control ­ prevented sesamed germination. POST summary: No known research.

SULFONAMIDE (Python)

PRE summary: Selective at lower rates, but toxic at higher rates. In the US in South Carolina, Culp and McWhorter (1965) cited Martin and Crawford (1963) who reported that sulfonamide caused slight to severe damage, but when it was tried at lower rates it caused no visible plant injury and gave weed control essentially equivalent to that obtained with CIPC. POST summary: No known research.

THIOBENCARB (Bolero)

PRE summary: Toxic to sesame with substantial stand reduction and less vigor than other treatments. In the US, in California, St Andre (1973) conducted PPI trials under furrow irrigation, planted 15 May. Variety was 247 (nonshattering). Evaluated 14 Jun. Note that the stands are much lower

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than the other St Andre testing. Nonshattering (indehiscent) lines have much less vigor than semi-shattering or shattering lines.

Stand count a Herbicide Rate Sesame Sesame Mustard Japanese Pigweed lb/ac vigorb millet Bolero (thiobencarb) 4.0 8.5 7.2 8.5 0.7 48 8.0 6.3 0.5 5.2 0.2 28 Untreated --10 12.2 7.5 5.5 23 a Stand count values represent the average number of plants in 8 feet of row in 4 replications except for the pigweed which was only present in the 3rd replication. b Vigor evaluation is based on a 0-10 scale with 0 = very poor vigor and 10 = vigorous growing plants.

Bolero reduced sesame stands substantially and the plants had less vigor than most of the treatments. It had good control of the Japanese millet, but poor control of the other two weeds. POST summary: No known research.

TRIASULFURON (Amber)

PRE summary: No known research, but mixed results in planting sesame after herbicide used in previous cereal crop. In the US, there are many wheat farmers that apply sulfuron products late in the wheat crop to control broadleaf weeds. There are been mixed results in planting sesame after these products. POST summary: No known research.

TRIFLOXYSULFURON (Envoke)

PRE summary: No known research, but mixed results in planting sesame after herbicide used in previous cereal crop. In Argentina in Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3 replications. There were 3 rains before emergence. The POST OTT herbicides were applied 19 days after planting. The weed control data was taken 13 days after application and was as follows:

Herbicide Envoke Active ingredient Rate/ha Ama a Trifloxysulfuron 10 g 20 Weed-free check 100 Weedy check 0 Weed control with 0 = no control and 100 = complete control. Rha = Raphanus sativus Rha a 100 100 0 Ama = Amaranthus quitensis and

a

There were three ratings done 13, 43, and 70 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight from capsules in the center of the capsule zone. The number of seeds

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were counted and the seed weight per capsule (SWC) and was taken. The POST OTT data was as follows:

13 43 DDAa DDA Trifloxysulfuron 0 5 Weed-free check 81 83 Weedy check 75 71 a DDA = days after application Active ingredient 70 DDA 5 78 65 Yieldg (g/m) 48.4 ab 50.7 ab W100 (g) 0.300 0.300 Sd/cap SWC (g) 0.222 0.188

74.1 62.8

The trifloxysulfuron destroyed the sesame stand entirely. POST DIR summary: Shows stunting, but recovers and had little reduction in yield. In further testing in 2007. Grichar, Dotray, and Langham experimented with POST DIR treatments in Uvalde and Lubbock in 2006. The experiment is being repeated in 2007. The variety used was Sesaco 29 planted 25 May in Uvalde and 20 June in Lubbock. The herbicides were applied 2" and 6" from the ground on both sides of the stem when the plants were about 18" tall in the juvenile stage. The treatments were replicated 3 times. In Uvalde the experiment was under a lateral pivot with extreme variation. As a result the yield data was taken by cutting a sample within the treatment and a sample in the adjacent untreated row. The yield below is a percent of the treated row divided by the untreated row. The Lubbock experiment was rainfed with some variation between rows, and the percentage yield below represents the treatment plot divided by the check plot. In both locations the day after planting, a PRE treatment of metolachlor plus glyphosate was sprayed over the fields. There was no weed pressure in either location since the purpose of the initial experiment was to find herbicides that would be selective to sesame.

Active ingredient Trifloxysulfuron Rate lbs/ ac 0.007 Height of applic 2" 6" Stunting Lub 0 3 Uva Yield % of check Lub Uva 96 123 86 81

Trifloxysulfuron shows some promise with minor reduction in yield. However, there was some chlorosis shortly after application which could make some farmers leery of application.

TRIFLURALIN (Treflan, Agriflan.

Treflan TR-10 does not require PPI)

Sesame use: Used in commercial fields as PPI and POST. No label in US. PRE summary: Mixed results ­ selective to sesame and very good weed control, but can be toxic to sesame in some cases. The method of incorporation is important in that trifluralin is selective to sesame when the seed line is below the herbicide, and the herbicide does not move down to the root zone at the seedling stage. Have not done much research using new products that do not require PPI. There has been limited work done on the recent formulations that allow trifluralin to be a PRE instead of a PPI herbicide. In the US, Weiss (1971) cited Martin (1963, 1964) who reported that trifluralin at 2.5 lb/ac killed or damaged sesame in all tests, but that at 1.1 to 1.6 kg/ha trifluralin was effective and non-toxic. In Venezuela, Montilla (1964) had one experiment with Treflan (trifluralin). He tried

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Treflan (1, 2, 3 l/ha) and Treflan/Dymid (4+1, 4+2, and 6+1 l/ha) as a pre-plant incorporated. The sesame did not germinate in any of the treatments. In Trinidad, Weiss (1971) cites L. Kasasian (1967, 1968) that trifluralin was too toxic. In the US in California, St Andre (1969) conducted PPI trials under furrow irrigation, planted 10 Jun. Variety was Baco planted at 2.5 lbs/ac. The stand counts were done 5 Jun and the ratings 10 Jun.

Rate lb/ac Trefmidc (trifluralin + .25 + 40.3 5.0 diphenamid) 4.0 Untreated --55.3 21.6 0 0 a Stand count values represent the average number of plants in 8 feet of row b Ratings based on 0-10 scale. 0 = no control or injury. 10 = perfect control or very severe injury. Injury rating reflects retardation and vigor in the growth of sesame. Herbicide Stand count a Sesame Barley Visual rating b Barley Sesame control injury 5.6 5.6

Trifluralin was not the best herbicide in the test in either low sesame injury or good weed control. In the US in California, Fischer (1971) summarized the work that had been done between 1967 and 1970 in the San Joaquin valley to include the results of St Andre (1969, 1970a, and 1970b). In that area the concept was to grow sesame double cropped after barley or other cereals, and thus the emphasis was on controlling volunteer grasses. He summarized the results for the years as follows:

Trade name Treflan Trefmid Active ingredient Trifluralin Trifluralin + Diphenamid Lbs/ac evaluated 0.75/1.5 0.25/4.0 on each Sesame tolerance Poor Poor Barley control Erratic Good

In Ethiopia, Moore (1973b, 1974) carried out a trial in the higher rainfall area at Setit Humera where irrigation was not necessary. Trifluralin at 0.75 kg and 1.4 kg/ha PPI and alachlor at 2.9 kg/ha applied PRE gave the highest yields of sesame. In Bulgaria, Georgiev (1980) concluded that on the basis of trials at Sadovo between 1974 and 1979, suitable herbicides for weed control in sesame included: Agriflan (trifluralin) at 2 l/ha applied PPI to a depth of 8 to 10 cm. The quality and fat content of sesame seeds were not adversely affected by these treatments. In Egypt, Hussien et al. (1983) studied trifluralin PPI. Two checks were used ­ one hand-hoed and the other with weeds. Trifluralin showed superiority in controlling annual grasses. Trifluralin at 1.6 kg/ha was a harmful treatment; however it produced an increase of 45% as compared to the unweeded check. Increase in seed yield by hand-hoeing was about 30% compared to the unweeded check. Seed oil content of sesame was not affected by the weed control treatments. In the US in Arizona, Howell et al. (1984) had the following results:

Treat PPI PPI PPI PPI Herbicide Treflan (trifluralin) Treflan (trifluralin) + Caparol (prometryn) Treflan (trifluralin) + Rate /ac 0.75 l 0.75 l 0.75 l 0.75 l Mid stunt No/OK OK/OK no/no Mid stand OK/OK OK/OK no/no Broadleaf control no/no OK/OK OK/OK Grass control OK/OK OK/OK OK/OK Early vigor OK/OK OK/OK no/no

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Treat PRE

Herbicide Caparol (prometryn)

Rate /ac 0.75 l

Mid stunt

Mid stand

Broadleaf control

Grass control

Early vigor

They concluded that there was not enough broadleaf weed control and some stunting with trifluralin by itself, but with PPI prometryn it was only one of three treatments with OKs across the board. In Australia in Queensland, Schrodter and Rawson (1984) evaluated PRE herbicides on sesame grown under weed free and weedy conditions in 3 experiments over two years. The following were the results of the first two experiments:

Herbicide Trifluralin (PPI) Rate kg/ha 0.84 1.68 Number of plants a 24 d b 13 d 59 a 52 ac Yield kg/ha 221 bc 113 cd 431 a 55d Number of plants Yield kg/ha Plant height cm d

Weed free control 251 b 385 b Weedy control 322 a 431 ab a 1000s/ha b Means not followed by a common letter differ significantly (P<0.05) c Experiment says PRE but probably PPI d Measured 29 days after planting

18 abc 20 a

The results of experiment 1 were as follows: · Trifluralin and chlorthal-dimethyl caused severe visible damage, and thus were not planted in Experiment 2. The lower rate of chorthal-dimethyl was not as bad as the higher rate · Yield in the weedy control was reduced 87% when compared to the weed free control. The weed free control significantly outyielded all the treatments except for the high rate of alachlor. In Israel, Graph et al. (1985) showed that PPI of trifluralin 0.125-0.188 kg/ha was selective to sesame when the crop was sown on relatively warm soil. Early sowing of trifluralin resulted in inhibited root growth due to cold soil, retardation, and crop damage. PRE treatment with 1.0-2.0 kg/ha of alachlor was selective to sesame but caused damage when applied with a PPI trifluralin treatment. In Korea, Kim et al. (1986) conducted field trials to study the herbicide efficacy and phytotoxicity in crops grown under polyethylene film. Most effective overall weed control was obtained using 0.67 kg/ha trifluralin, but it caused crop damage and yield reductions. 3 l/ha napropamide or 1.5 l/ha alachlor gave sesame yields equivalent to that obtained with manual weed control. In Australia in the Northern Territories, a grower guide (Bennett 1998) states that grass weeds can be fairly easily controlled in a conventionally tilled sesame crop using PRE herbicides such as Treflan. In South Texas, Grichar et al. (2001a) conducted field studies from 1994 through 1997 in Yoakum and in Uvalde in 1995 to evaluate soil-applied herbicides for weed control, sesame tolerance, and yield. There were four replications. The varieties used were Sesaco 11, 17, or 18. The plant height was taken from averaging 5 plants and taken 5-7 weeks after planting. The data is as follows:

Herbicide Trifluralin Check Rate kg/ha 0.4 0.8 Applic PPI PPI 1994 5 WAP a 40.4 35.6 43.4 Sesame height (cm) 1995 1996 7 WAP 6 WAP 113.3 50.8 49.3 b 55.4 b 131.3 43.4 1997 5 WAP 74.4 70.3 70.9

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Herbicide Applic LSD (0.05) a WAP = weeks after planting b Significantly different from check

Rate kg/ha

1994 5 WAP a 16.9

Sesame height (cm) 1995 1996 7 WAP 6 WAP 31.0 11.6

1997 5 WAP 14.7

Trifluralin significantly reduced the height in one trial and yet significantly increased it in another. The sesame population was counted 4-6 weeks after planting. The data was as follows:

Plants/m of row Herbicide Applic Trifluralin PPI Trifluralin PPI Check LSD (0.05) a Significantly different from check Rate kg/ha 0.4 0.8 1995 14.0 a 1.5 a 70.3 23.5 1996 45.5 37.0 65.3 36.1 1997 22.8 a 14.1 a 67.5 18.8

Trifluralin lowered the populations significantly except for 1996. The dinitroaniline herbicides were incorporated 2.5 cm deep which may have resulted in contact with the seed. The chemicals also may have moved down with moisture to be in contact. The weed control is based on 0 = not control and 100 = complete control. The weed control data was as follows:

Herbicide Trifluralin Trifluralin Check LSD (0.05) Rate kg/ha 0.4 0.8 Applic PPI PPI Broadleaf signalgrass 63 54 0 21 Brown-top panicum 100 100 0 10 Southern cragrass 98 100 0 18 Palmer amaranth 1994 1995 37 47 0 25 99 97 0 4

Trifluralin provides good grass control but were erratic on broadleaf control as would be expected. The weed control data was as follows:

Rate Herbicide kg/ha Applic Trifluralin 0.4 PPI Trifluralin 0.8 PPI Check LSD (0.05) a Significantly different from check 1994 Yoakum 950 a 540 650 300 1995 Yoakum 1470 a 870 310 1995 Uvalde 1570 a 1500 a 870 470 1996 Yoakum 740 700 480 450 1997 Yoakum 670 a 660 a 480 180

The data in the following table was converted to a percentage yield compared to the check, but the average did not include 1996 where all of the herbicides exceeded the yields of the check.

Herbicide Trifluralin Trifluralin

a

Rate kg/ha 0.4 0.8

Applic PPI PPI

1994 Yoakum 146 a 83

1995 Yoakum 169 a

1995 Uvalde 180 a 172 a

1996 Yoakum 154 146

1997 Yoakum 140 a 138 a

Average 159 134

Significantly different from check

By looking at the data in this way, it goes back to what Grichar said in the beginning that sesame with few weeds + some herbicide damage to the sesame is better than a lot of weeds + no damage to the sesame. Sesame has the ability to compensate for low stands by setting branches that load up with capsules. They concluded that trifluralin is a good option for weed control but crop safety is a concern if the herbicide is incorporated too deep in a shallow planted crop. In India in Haryana, Punia et al. (2001) conducted an experiment on sandy loam soil during kharif 1999 and 2000, to investigate the efficacy of hebicides against weeds in sesame (cv. HY-1). Treatments included trifluralin 1.0, 1.25 and 1.5 kg/ha and integration of each of these herbicides

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with one hoeing at 4 weeks after sowing (WAS). Trifluralin was applied PPI in 2-3 cm top soil. On an average, season long weed competition caused 61% reduction in seed yield. Two hoeings at 3 and 6 WAS, integration of either fluchloralin, pendimethalin or trifluralin at 1.0 kg/ha with one hoeing at 4 WAS were significantly better in terms of weed control efficiency and seed yield compared to one hoeing at 4 WAS or herbicides used alone. In Honduras, a grower guide (Anon 2002) states that the use of PRE herbicides such as trifluralin (Treflan) has proved to be very efficient in the control of weeds in sesame. In India in Rajasthan, Dungarwal et al. (2003) conducted a field experiment during the kharif seasons of 1997 and 1998 to evaluate the relative efficacy of trifluralin applied alone or in combination with one hoeing at four weeks after sowing ( WAS) to control weeds in sesame (cv. TC 25). On average, season-long weed competition caused 50% reduction in seed yield. Integration of trifluralin at 1.0 kg/ha or at 2.0 kg/ha with one hoeing at 4 WAS was more effective when assessed in terms of weed control efficiency and seed yield compared to their single application. Among the herbicides, alachlor and fluchoralin combined with one hoeing at 4 WAS were the best treatments. In Costa Rica, a grower guide (Anon 2007d) recommends using one PRE application of trifluralin (Treflan at 2 l/ha). In Australia, Jim Barnes (2007, pers. commun.): "PRE use of Treflan (trifluralin) was OK but in our environment it requires incorporation which can be difficult. Some of our farmers were zero till farmers so incorporation was not possible." In Argentina in Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3 replications. There were 3 rains before emergence. The PRE test populations and weed control are as follows:

Weed control a 19 DDA b Herbicide Trifluralina

a a

30 DDA

Active ingredient Rate/ha Stand Ama Rha Ama Rha Trifluralin c 1.5 l 3.9 50 60 85 60 Clean check 4.1 100 100 100 100 Weedy check 3.2 0 0 0 0 a Weed control with 0 = no control and 100 = complete control. Ama = Amaranthus quitensis and Rha = Raphanus sativus b DDA = days after application c Used the variants that do not require PPI.

There were four ratings done 19, 30, 60, and 88 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight of capsules in the center of the capsule zone. The number of seeds were counted and the seed weight per capsule (SWC) and was taken. The PRE data was as follows:

19 DDA Trifluralin 73 Clean check 83 Weedy check 77 a DDA = days after application Active ingredient 30 DDA 70 87 77 60 DDA 73 88 78 88 DDA 75 82 72 Yield (g/m) 55.7 cde 59.9 de 53.8 bcde W100 (g) 0.289 0.284 0.297 Sd/cap 64 71 69 SWC (g) 0.185 0.202 0.205

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Trifluralin had a comparable yield to the weedy check, but the main problem was that it did not control the weeds as well as other potential herbicides. In Australia in the Northern Territories, M. Bennett (2007) stated that the research in the Northern Territories had concentrated on summer grass control. Treflan (trifluralin) applied at low rates (1.0 L/ha) on soils where sand content is less than 50 to 70% suppressed grass weed development with minimal reduction to sesame plant numbers. He also reports that other oilseed herbicides will be tested in the near future to include several brands of trifluralin. In the US, the first author has made the following observations: · In the first year of planting in Texas, a full cotton label rate (differs in areas) of trifluralin was used, and there was enough of a stand reduction that a half rate (0.5 l/ha) was tried successfully. · The practice in the nurseries was to pre-irrigate, apply the trifluralin at half cotton rate, incorporate it with a harrow, and plant. The trifluralin did a good job controlling grasses and pigweed, but it did not control copperleaf (Acalypha ostryifolia). · In some years in pulling up plants, there was some root pruning, but the plants still matured and looked normal. There was never an attempt to see if the trifluralin had lowered the yield. In the yield sampling in the breeding program, the averages changed from year to year, but the changes could always be correlated to irrigations, fertility, and weather. There was never any reason to suspect that the trifluralin affected the yield in a negative way, but it did affect the yield in a positive way by controlling weeds. · In 1997 there was a heavy rain about 10 days after planting, and the majority of the nursery died off. In pulling up plants that died next to ones that survived, the roots were pruned off the dying plants. The nursery had to be replanted. The author had been cooperating with Grichar (2001a), and both felt that metolachlor (Dual) would provide good control with minimum damage to the sesame, and metolachlor has been used since then. · Starting back in 1987 there has been sesame planted after hailed out cotton. Trifluralin had been applied prior to planting with different practices ­ some apply it in February/March and others apply it closer to the planting of cotton that ranges from late April to early June. With US insurance policies if there is a hail out prior to a certain date (the date varies with the area), then cotton has to be replanted, but after that any crop can be planted. Most of the sesame planted after hailed out cotton has occurred in the mid June to early July time-frame. There has never been a loss of a sesame stand after hailed out cotton due to trifluralin. It is not known if there is no effect because the trifluralin has been diluted through rains into different ranges of soil, or if the trifluralin loses its potency over time, or the trifluralin is less effective against sesame in warmer soils. · In using trifluralin it is critical to place the seed in the moisture below the hot zone of the herbicide. Dry soil with trifluralin has been pulled over the seed line has no effect. There have been problems when there is a rain after the trifluralin has been applied/incorporated and before planting. In these cases, the seed is placed in the hot zone, and the stand can be damaged or even lost. · In cold weather, sesame takes longer to germinate and grows even more slowly. Trifluralin appears to damage the plants more when under cool conditions than when it is warmer and the sesame germinates and grows faster. · In most uses, trifluralin does a good job in controlling weeds with little effect on sesame; however, there have been fields that were completely lost because of the trifluralin reducing stands. · As more and more farmers move to no-till practices, trifluralin will not be as good an option since it has to be incorporated or it will lose its effectiveness. There is very limited data on

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trifluralin products that can be applied PRE instead of PPI. The only known experiment was done in Argentina by Lanfranconi et al. (2007). POST summary: No known research. Trifluralin characteristics: (Anon 1994, 1998) · Other crop uses: Has been used as PPI, PRE, POST, and POST DIR. It controls primarily grass weeds and certain small seeded broadleaf weeds. It can be applied in liquid fertilizer, impregnated on dry bulk fertilizer, or through chemigation systems. · Description: Orange crystalline solid, no appreciable odor. · Symptomology: Highly susceptible annual grasses and broadleaves fail to emerge due to inhibition of coleoptile growth or hypocotyl unhooking. It does not prevent the seed from germinating. Root growth inhibition is a prominent symptom on emerged seedlings and established plants, particularly in development of lateral and secondary roots. Shoots may be deformed and brittle. · Absorption/translocation: Absorbed primarily by emerging plant shoots (coleoptile, hypocotyl, or epicotyl), secondarily by seedling roots. Plants beyond the seedling stage absorb trifluralin into the roots but translocation to shoots is limited. · Mechanism of action: It affects the mitosis of cells at the end of the roots. · Sorption: Strongly adsorbed to soil, more tightly to OM than clay. · Transformation: - Photodegradation: Degraded by UV light. - Other degradation: Degraded microbially, more rapidly in flooded anaerobic than in moist aerobic soils. · Persistence: Average half-life in the field is 45 days on most soils with typically <10% of applied trifluralin remaining 1 year after application. Half-life is longer in cool, dry areas and may be up to 120 days. Residues of trifluralin applied at 1.1 kg ai/ha may persist into the following season enough to injure rotational crops such as corn. · Mobility: Low to negligible leaching potential due to strong adsorption to soil. · Volatilization: Is slightly volatile leading to small but significant losses when left unincorporated. On moist soil granule formulations are less susceptible to losses by volatilization and photodecomposition. · Miscellaneous information:

Common name Trade name Date Avg rate (lbs/ac) Trifluralin Treflan 1963 0.75 Current sample of label: (http://www.dowagro.com/usag/prod/055.htm) LD50 rat (mg/kg) 500

Using the sample label above for Treflan TR-10, there are rotational restrictions from immediate to 12 months depending on the crop, the rainfall, and the amount of the herbicide used. Refer to the current label for current restrictions.

VERNOLATE (Vernam)

PRE summary: Toxic to sesame. In the US in California, Fischer (1971) summarized the work that had been done between 1967 and 1970 in the San Joaquin valley to include the results of St Andre (1969, 1970a, and 1970b). In that area the concept was to grow sesame double cropped after barley or other cereals, and thus the emphasis was on controlling volunteer grasses. He summarized the results for the years as follows:

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Trade name Vernam

Active ingredient Vernolate

Lbs/ac evaluated 3.0

Sesame tolerance Poor

Barley control Good

POST summary: No known research.

ACKNOWLEDGEMENT

This information has been gathered with the support of Sesaco Corporation and the American Sesame Growers Association.

BIBLIOGRAPHY

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Culp, T.W, and G.G. McWhorter. 1965. CICP and other herbicides for weed control in sesame (Sesamum indicum), Weeds, 13(4). Dungaral, H.S., P.C. Chaplot, and B.L. Nagda. 2003. Integrated weed management in sesame (Sesamum indicum L.), Indian Journal of Weed Science 35(3/4): 236-238. Eagleton, G., S. Sandover, and M. Dickinson. 1987. Research report: sesame seed 1982-1986, Dept. Agric. Kununurra, West Australia. Fischer, B.B. 1971. Herbicides for Weed Control in Sesame, California Agriculture Georgiev, S. 1980. Effectiveness of some herbicides on the control of weds on sesame fields, Rasteniev dni Nauki 15(7): 70-76. Ghosh, D.C., and S.K. Mukhopadhyay. 1980. Weeds and weed control in sesame. Pesticides 14(11), 24-29. Gnanavel, I., and R. Anbhazhagan. 2006. Integrated weed management in sesame (Sesamum indicum L.), Agricultural Science Digest 23(1): 67-68. Graph, S., Y. Kleifeld, G. Herzlinger, T. Blumenfeld, and A. Bargutti. 1985. Weed control in sesame, Phytoparasitica 13 (3/4): 259. Grichar, W. J., D.C. Sestak, K.D. Brewer, B.A. Besler, C.R. Stichler, and D.T. Smith. 2001a. Sesame (Sesamum indicum L.) tolerance and weed control with soil-applied herbicides. Crop Protect. 20:389-394. Grichar, W. J., D. C. Sestak, K. D. Brewer, B. A. Besler, C. R. Stichler, and D. T. Smith. 2001b. Sesame (Sesamum indicum L.) tolerance with various postemergence herbicides. Crop Protect. 20:685-689. Grichar, W.J. and D.R. Langham. 2003. POST over the top and harvest aid sesame experiments in 2003, unpublished. Grichar, W.J. and P.A. Dotray. 2007. Sesame tolerance to PRE and POST herbicides in 20042005, unpublished. Grichar, W.J., P.A. Dotray, and D.R. Langham. 2006. Harvest aid sesame experiments in 20052006, unpublished. Grichar, W.J., P.A. Dotray, and D.R. Langham. 2006. POST directed sesame experiments in 2006, unpublished. Gurnah, A.M. 1974. Critical weed competition periods in annual crops. Proceedings of the fifth East African Weed Control Conference, Nairobi, Kenya, pp. 89-98. Hussien, M.A., A.H. El-Hattab, M.S. Abd-El-Raouf, and S.A. Shaban. 1983. Effect of Soil Herbicides on Weed Yield and Quality of Sesamum Indicum L., Z. Acker. Pflanzenbou 152: 173185.

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Howell, Don, D.N. Byrne, and D. R. Langham. 1984. 1984 Herbicides Trials in Yuma, Arizona. Data collected by the Univ. of Arizona Extension and Sesaco Corporation, unpublished. Hussien, M. A., A.H. El-Hatlab, M.S. Abd-El Raouf, S.A. Shaban, and M.H. El-Deek. 1983. Effect of soil herbicides on weeds, yield and quality of sesame, Sesamum indicum. Pflanzenbou 152:173-185. Ibrahim, A.F., H.R.El Wekil, Z.R. Yehia, and S.A. Shaban. 1988. Effect of some weed control treatments on sesame (Sesamum indicum L.) and associated weeds, Journal of Agronomy and crop Science 160(5): 319-324. Jain, G. L., S. M. Singhi, M. P. Sahn, and G. L. Sharma. 1985. Sesame production in Rajasthanconstraints and opportunities. In H. C. Srivastava, S. Bhaskaran, B. Vatsya, and K. K. G. Menon (eds.). Oilseed Production Constraints and Opportunities. New Delhi, India. pp. 181-198. Joshi, P. 1985. Sesame production in Rajasthan ­ constraints and opportunities. In: Srivastava, H.C., Bhaskaran, S., Vatsya, B., Menon, K.K.G.(Eds.), Oilseed Production Constraints and Opportunities. New Delphi, pp. 199-204. Kasasian, L. 1967. Ann. Rept. Hebicide Section, Dept. Crop Sci., Univ. West Indies, Trinidad. Kasasian, L. 1968. Herbicide Agronomist. Herb. Res. Unit, Univ. West Ind.,Kingston, Jamaica.Pers. comm. to E.A. Weiss. Kim, J.I., C.K. Kang, S.M. Oh, and H.S. Lee. 1986. Studies on the weed control and phytotoxicity of herbicides under polyethylene film mulching in the sesame upland In field trials in the sesame-producing uplands, Research of the Rural Development Administration, Plant environment Mycology and Farm Products Utilization, Korea Republic 28(2): 72-78. Lanfranconi, L., L. Remondino, and A. Calderoni. 2007. Evaluacion de herbicidas en el cultivo de sesamo, Pocoy, Salta, unpublished. Langham, D.G. and M. Rodriguez. 1945. El ajonjoli (Sesamum indicum L.): su cultivo, explotacion, y mejoramiento. Bol. 2, Publ. Ministerio de Agricultura y Cria, Maracay, Venezuela. p. 132. Langham, D.R. and T. Wiemers. 2002. Progress in mechanizing sesame in the US through breeding. p. 157­173. In: J. Janick and A. Whipkey (ed.), Trends in new crops and new uses. ASHS Press, Alexandria, VA. Langham, D.R. 2007. The phenology of sesame, in press. Lee, J.I. 1986. Sesame breeding and agronomy in Korea. Crop Experiment Station, Rural Development Administration, p. 61. Lyubenov, Y. and K. Kostadinov. 1970. Possibilities for chemical weed control in sesame (Sesamum indicum). Preliminary Project, Rastitelna Zashchita (4): 31-35. Malik, N.A. and Muhammed-Ramzan. 1992. Effect of herbicides and cultural operations on weed control and grain yield sesame, Journal of Agricultural Research Lahore 30(1): 147-152.

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Mani, A.P. 1961. Chemical control of weeds in some important dicotyledonous crops of West Bengal.-Trans. Bose.Res. Inst. 24(2), 83-93. Martin, C. C. 1995. Development of an effective weed control system for sesame in the Northern Territory. Proceedings of Sesame Workshop, Darwin and Katherine, New Territory. pp. 121-127. Martin, J.A. and J.H. Crawford. 1963. Sesame and Castorbean research in South Carolina, Res. Ser. 41, S.C. Agri. Exp. Sta., Clemson, S.C. Martin, J. A. 1964. Sesame and Castorbean Research in South Carolina.-Res.Ser. 59 South Carolina Agric. Expt. Stn .,Clemson, South Carolina, U.S.A. Mazzani, Bruno. 1957. Mejoramiento del ajonjoli en Venezuela, Ministerio de Agricultura y Cria, Maracay, Ven., p. 127. Mazzani, Bruno. 1966. El cultivo del ajonjoli.-Agronomia 3(5-6), 1-10. Mazzani, Bruno. 1999. Investigación y Tecnología del Cultivo del Ajojonlí en Venezuela Montilla, D. 1964. Resultados de Pruebas de Algunos Herbicidas en el Cultivo de Ajonjoli en Turen, Agronomia, Tropical Venez. 14(3) Moore, J.E. 1973a. Sesame herbicide trial-setit Humera. Progress Report for the Period April 1972 to March 1973, Ethiopia Institute of Agricultural Research Station Sesame herbicide screening trial Melka Werer 175-177. Moore, J.E. 1973b. Sesame herbicide screening trial-Melka Werer, Progress Report for the period April 1972 to March 1973 168-174. Moore, J.E. 1974. Evaluation of herbicides in irrigated and raingrown sesame in the lowlands of Ethiopia, Proceedings of the Fifth East African Weed Control Conference 16th 18th January 1974,Nairobi,Kenya 108-130. O'Shanesy, Penny. 2000. Open Sesame! A Case Study on Supply Chain Marketing, Farming Systems Institute, Queensland Department of Primary Industries. Om, Prakash, B.P. Singh, and P.K. Singh. 2001. Effect of weed- control measures and nitrogen ertilization on yield and yield attributes of sesame (Sesamum indicum) under rainfed condition, Indian Journal of Agricultural Sciences 71(9): 610-612. Panhwar. 2005. Oilseeds crop future in Sindh Pakistan. Pineda P., Juan B. and Jesus M. Avila M. 1988. Alternativas para el control de Macrophomina phaseolina y Fusarium oxysporum pategenos del ajonjoli (Sesamum indicum L, Agronomía Tropical. 38(4-6): 79-84 Punia, S.S., R. Mayank, Y. Ashkok, and R.K. Malik. 2001. Bioefficacy of dinitroaniline herbicides against weeds in sesame (Sesamum indicum L.), Indian Journal of Weed Science 33(3/4): 143-146.

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Sapin, V., G. Mills, D. Schmidt, and P. O'Shanesy. 2000. Growing sesame in South Burnett. Department of Primary Industries, Queensland Government, www.dpi.qld.gov.au/fieldcrops/2888.html, accessed Nov 2003. Schrodter, G.N. and J.E. Rawson. 1984. Herbicide evaluation studies in sesame, Australian Weeds 3(2), 47-49. Sharma, S.M. 1985. Constraints and opportunities for increasing the productivity and production of sesame in India. In: Srivastava, H.C., Bhaskaran, S., Vatsya, B., Menon, K.K.G. (Eds.), Oilseed Production Constraints and Opportunities. New Delhi, Oxford & IBH Publishing Co. pp. 165-179. Shukla, V. 1984. Chemical weed control in sesame, Pesticides 18(3): 13-14. Singh, D., J.C. Dagar, and B. Gangwar. 1992. Infestation by weeds and their management in oilseed crops ­ a review. Agric. Rev. 13,163-175. Sootrakar, B.P., K.N. Namedo, and L.J. Khare. 1995. Effect of weed control on productivity of sesame (Sesamum indicum), Indian Journal of Agronomy 40(3): 454-458. St. Andre, J. 1969. Sesame weed control trial 1969. University of California Cooperative Extension, unpublished. St. Andre, J. 1970a. Sesame weed control trial 1970 on a single crop. University of California Cooperative Extension, unpublished. St. Andre, J. 1970b. Sesame weed control trial 1970 on a double crop. University of California Cooperative Extension, unpublished. St. Andre, J. 1973. Sesame weed control trial 1973. University of California Cooperative Extension, unpublished. St. Andre, J. 1974. Sesame weed control trial 1974. University of California Cooperative Extension, unpublished. St. Andre, J. 1978. Sesame weed control trial 1978. University of California Cooperative Extension, unpublished. Soto-Soto, E. and J.M. Silva-Vasquez. 1987. Trials of pre-emergence in the cultivation of sesame (Sesamum indicum L.), Informe de Las Labores de la Seccion de Agronomica Centro Experimental del Algodon 131-145. Subramanian, A. and S. Sankaran. 1977. Studies on the relative efficiency of preemergence herbicides in sesamum under graded levels of nitrogen, Program-and-Abstracts of Papers, Weed Science Conference and Workshop in India (Paper 63): 37-38. Subramanian, A. and S. Sankaran. 1981. Chemical weed control of common pursulane (Trianthema portulacastrum L.), Abstracts of Papers, annual conference of Indian Society of Weed Science, undated 26.

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Tocquigny, J.R. and G.A. Livingston. 1953. Weed control tests in sesame, Weed Conf. Proc. 6. Upadhyay, U.C. 1985. Weed management in oilseed crops. In: Srivastava, H.C., Bhaskaran, S., Vatsya, B., Menon, K.K.G. (Eds.), Oilseed Production Constraints and Opportunities. New Delhi, pp. 491-499. Viera, D.J., N.E. Beltrao, L.B. Nobrega, D.M. Azevedo, and J.N. Oliveira. 1998. Chemical control of weeds in sesame crop, Communicado Technico Embrapa Algodao (72): 8 pp. Warfa, A.M. and M.A. Noor. 1978. The residual effect of Gesaprim in various crops, Studi-e-Ricerche 2(2): 125-129. Weiss, E.A. 1971. Castor, sesame, and safflower. Leonard Hill Books, London. p. 311­525. Yadav, S.S. 2004. Integrated weed management in sesame (Sesamum indicum L.) under rainfed conditions of Rajashan, Haryana Journal of Agronomy 20(1/2):120-121. Sewdie, K. 1994. Effect of pre- and post-emergence herbicides on weed control and yield of sesame under irrigation, Proceedings of the Ethiopian Weed Science Society, Addis Abeba (Ethiopia), 15-16 Dec 1994.

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Appendix 1. Sesame herbicide research by country

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APPENDIX 1. REVIEW OF SESAME HERBICIDE RESEARCH BY COUNTRY

The following summarizes the herbicide research broken down alphabetically by country, and chronologically within country. Some researchers use the name of the active ingredient instead of trade names, and others use the trade name instead of the active ingredient. In the cases where they use only the trade name, the author has added the active ingredient. Appendix 2 provides a cross-reference tables arranged alphabetical by trade name. ARGENTINA In Salta, Lanfranconi et al. (2007) conducted PRE and POST OTT experiments. The field was planted 1 Feb and the applications were made the same day. There were 3 replications. There were 3 rains before emergence. The PRE test populations and weed control are as follows:

Weed control a 19 DDA b Herbicide Sumisoya Gesapax Brodal Dual Teliron Active ingredient Flumioxazin Ametryn Diflufenican Metolachlor Linuron Rate/ha 70 cc 3 kg 300 cc 1.2 l 1.5 l 2.0 l 1.5 l 2.5 l 2.0 l 90 g 30 g 700 cc 1.3 l 2.0 l 500 cc 1.5 l

a a

30 DDA

Stand Ama Rha Ama Rha 0.2 100 95 100 99 0 100 55 100 45 1.3 100 85 95 85 2.5 100 40 70 50 3.9 90 85 90 95 3.9 90 90 85 100 Gesagard Prometryn 0.2 100 90 100 90 Herbadox Pendimethalin c 1.1 85 55 90 85 Command Clomazone 1.3 50 75 65 80 Preside Flumetsulam 2.2 85 0 80 0 Spider Diclosulam 0 100 85 100 95 Sencorex Metribuzim 1.3 100 65 100 60 Ronstar Oxadiazon 1.8 95 55 85 65 1.8 95 55 95 80 Authority Sulfentrazone 0 100 90 100 99 c Trifluralina Trifluralin 3.9 50 60 85 60 Clean check 4.1 100 100 100 100 Weedy check 3.2 0 0 0 0 a Weed control with 0 = no control and 100 = complete control. Ama = Amaranthus quitensis and Rha = Raphanus sativus b DDA = days after application c Used the variants that do not require PPI.

There were four ratings done 19, 30, 60, and 88 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight of capsules in the center of the capsule zone. The number of seeds were counted and the seed weight per capsule (SWC) and was taken. The PRE data was as follows:

Active ingredient Flumioxazin Ametryn Diflufenican Metolachlor Linuron low rate Linuron high rate 19 DDA 0 0 10 73 90 85 30 DDA 2 0 13 78 88 85 60 DDA 0 0 10 63 100 90 88 DDA 8 2 53 73 97 83 Yield (g/m) W100 (g) Sd/cap SWC (g)

42.5 abcd 58.0 cde 68.5 e 57.9 cde

0.284 0.289 0.320 0.302

68 73 65 68

0.193 0.211 0.208 0.205

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19 DDA Prometryn 0 Pendimethalin 3 Clomazone 10 Flumetsulam 13 Diclosulam 0 Metribuzim 7 Oxadiazon low rate 10 Oxadiazon high rate 5 Sulfentrazone 0 Trifluralin 73 Clean check 83 Weedy check 77 a DDA = days after application Active ingredient

30 DDA 3 12 18 17 3 17 12 5 0 70 87 77

60 DDA 0 47 45 47 5 5 48 53 0 73 88 78

88 DDA 5 50 42 43 3 8 53 47 5 75 82 72

Yield (g/m) 47.5 abcd 33.1 a 33.5 ab

W100 (g) 0.274 0.265 0.269

Sd/cap 68 67 60

SWC (g) 0.186 0.178 0.161

38.0 abc 38.1 abc 55.7 cde 59.9 de 53.8 bcde

0.290 0.287 0.289 0.284 0.297

67 63 64 71 69

0.194 0.181 0.185 0.202 0.205

Their conclusions on PRE were as follows: · There were 6 herbicides that prevented germination: flumioxazin, ametryn, prometryn, diclosulam, metribuzim, and sulfentrazone. · Linuron was the best herbicide for both selectivity to sesame and good weed control. · Metolachlor and trifluralin had some selectivity to sesame with some reduction in yield, but they did not have good weed control. · All other products were somewhat selective to sesame, but there was substantial yield reduction. The POST OTT herbicides were applied 19 days after planting. The weed control data was taken 13 days after application and was as follows:

Herbicide Gesagard Cobra Basagran Flex Weedex Preside Ronstar Ecopart Envoke Cadre Sumisoya Callisto Brodal Equip Active ingredient Prometryn Lactofen Bentazon Fomesafen Rate/ha 2000 cc 300 cc 1400 cc 350 cc 700 cc 1000 cc 300 cc 1300 cc 100 cc 10 g 72 g 70 cc 300 cc 100 cc 120g Ama a 100 100 40 85 55 40 100 50 10 20 100 50 100 50 100 Rha a 100 100 100 80 90 95 100 30 100 100 100 90 100 90 100

a

Bromoxynil Flumetsulam Oxadiazon Piraflufen ethyl Trifloxysulfuron Imazapic Flumioxazin Mesotrione Diflufenican Foramsulfuron + Iodosulfuron Weed-free check 100 100 Weedy check 0 0 Weed control with 0 = no control and 100 = complete control. Ama = Amaranthus quitensis and Rha = Raphanus sativus

There were three ratings done 13, 43, and 70 days after application, yield samples and capsule data was taken on the better treatments. The ratings took into account the population and the general health and height of the plants. The yield is the number of grams per meter. The W100 is the hundred seed weight from capsules in the center of the capsule zone. The number of seeds

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were counted and the seed weight per capsule (SWC) and was taken. The POST OTT data was as follows:

Active ingredient Prometryn Lactofen Bentazon Fomesafen low rate Fomesafen high rate Bromoxynil Flumetsulam Oxadiazon Piraflufen ethyl Trifloxysulfuron Imazapic Flumioxazin Mesotrione Diflufenican Foramsulfuron + 0 Iodosulfuron Weed-free check 81 Weedy check 75 a DDA = days after application 13 DDAa 0 5 20 30 8 28 5 53 57 0 5 42 0 55 43 DDA 0 12 18 18 5 28 0 88 88 5 0 83 0 78 0 83 71 70 DDA 2 17 18 30 8 37 0 78 77 5 0 73 0 65 2 78 65 Yieldg (g/m) W100 (g) Sd/cap SWC (g)

34.6 a 51.2 ab 41.0 ab

0.282 0.282 0.303

71.3 64.6 69.5

0.201 0.182 0.211

56.1 b 46.1 ab

0.288 0.300

73.6 62.5

0.212 0.188

48.4 ab 50.7 ab

0.300 0.300

74.1 62.8

0.222 0.188

Their conclusions on POST OTT were as follows: · There were 9 herbicides that destroyed the sesame stand: prometryn, lactofen, bentazon, fomesafen, flumetsulam, trifloxysulfuron, imazapic, mesotrione, and foramsulfuron + iodosulfuron. · Bromoxynil, piraflufen ethyl, and diflufenican were somewhat selective but reduced the yield substantially. · Flumioxazin and oxadiazon damaged the sesame initially, but the sesame recovered well and ended up with yields comparable to the checks. Neither had good weed control, but they must have set back the weeds for the sesame to canopy over because at the end the plots were relatively clean. AUSTRALIA In Queensland, Schrodter and Rawson (1984) evaluated PRE, PPI, and POST OTT herbicides on sesame grown under weed free and weedy conditions in Lockyer Valley in 4 experiments over two years. Cultivar 60/1B was planted in the first two experiments and Palmetto in the other two experiments. The POST OTT applications were done 21 days after planting while the plants were in the third true leaf stage. In the first POST experiment, the successful PRE treatments were repeated along with a POST treatment of bentazon. The following were the results of the first two experiments:

Herbicide Trifluralin (PPI) Alachlor (PRE) Chorthal-dimethyl Rate kg/ha 0.84 1.68 2.25 4.5 7.5 Exp 1 Number Yield of plants a kg/ha 24 d b 221 bc 13 d 113 cd 38 ad 133 bd 56 ab 295 ab 34 ad 147 bd Number of plants Exp 2 Yield kg/ha Plant height cm d

289 ab 307 ab

403 b 460 a

19 ab 17 bc

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Herbicide (PRE) Linuron (PRE)

Pendimethalin (PRE) c Weed free control 59 a 431 a Weedy control 52 ac 55d a 1000s/ha b Means not followed by a common letter differ significantly (P<0.05) c Experiment says PRE but probably PPI d Measured 29 days after planting

Rate kg/ha 15.0 1.1 2.2 1.5 3.0

Exp 1 Number Yield of plants a kg/ha 29 bcd 102 cd 62 a 144 bd

Number of plants 293 ab 278 ab 172 c 102 d 251 b 322 a

Exp 2 Yield kg/ha 414 ab 425 ab 118 c 22 d 385 b 431 ab

Plant height cm d 19 ab 16 c 6d 4d 18 abc 20 a

The results of experiment 1 were as follows: · Trifluralin and chorthal-dimethyl caused severe visible damage, and thus were not planted in Experiment 2. The lower rate of chorthal-dimethyl was not as bad as the higher rate · Alachlor and linuron had no significant effect on the populations · Yield in the weedy control was reduced 87% when compared to the weed free control. The weed free control significantly outyielded all the treatments except for the high rate of alachlor. The results of experiment 2 were as follows: · Pendimethalin reduced plant population, yield, and plant height. Plant maturity was delayed and was harvested 5 days later than the other treatments. · Alachlor and linuron had no effect on the crop. · The reduction of population in the weed free control was probably a loss during the hand weeding operation. In experiment 3, the successful treatments were repeated and a few new herbicides were tried as follows:

Herbicide Alachlor (PRE) Linuron (PRE) Bentazon (POST) e Rate kg/ha 2.25 2.25 0.96 Type of plot Weedy Weed free Weedy Weed free Weedy Weed free Weedy Number of plants a 230 a c 233 a 65 bc 122 b 85 bc 66 bc 7d Yield kg/ha 1051 a 953 a 634 bc 875 ab 210 e 545 cd 174 e Plant vigour rating b 4.8 a 4.8 a 2.8 c 3.5 b 1.5 d 1.5 d 0.3 e

Alachlor (PRE) 2.25 Bentazon (POST) 1.92 Linuron (PRE) 2.25 Weedy 49 c 327 de 1.5 d Bentazon (POST) 0.96 + Bentazon (POST)d 0.96 Weedy 7d 83 e 0.8 e Weedy control 259 a 579 c 4.9 a Weed free control 314 a 1075 a 5.0 a a 1000s/ha b Scale 0-5 with 0 = majority of plants dead, 5 = all plants healthy, uniform growth. Taken 29 days after planting. c Means not followed by a common letter differ significantly (P<0.05) d Publication table is missing something; must have had another herbicide ­ probably alachlor. e The POST application was 21 days after planting

The results of experiment 3 were as follows: · Weed competition in the weedy control reduced the yield by 46% when compared with the weed free control.

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· Alachlor was the safest herbicide with yield, population, and vigor similar to the weed free control. · The yield following treatment with linuron (weed free) was not significantly less that the weed free control but linuron (weedy) reduced yield, possibly because of incomplete weed control. Both linuron treatments reduced plant population and vigor. · All treatments using bentazon reduced yield, population, and vigor. · The overall conclusion was that alachlor at 2.25 kg/ha applied PRE was the most acceptable herbicide treatment. The fourth POST OTT experiment tried a few other POST herbicides with the following results:

Herbicide Bifenox Diphenamid Prometryn Bromoxynil Methabenthiazuron Rate kg/ha 2.0 6.0 2.0 0.28 0.42 0.7 1.4 Number of plants a 3bc 272 a 0 249 a 209 a 259 a 236 a 312 a 290 a Yield kg/ha 57 d 783 b 0 1077 a 802 ab 928 ab 940 ab 937 ab 492 c Plant vigour rating b 0d 4.7 a 0 3.7 b 2.3 c 2.7 c 2.7 c 5.0 a 5.0 a

Weed free control Weedy control a 1000s/ha b Scale 0-5 with 0 = majority of plants dead, 5 = all plants healthy, uniform growth. Taken 29 days after planting. c Means not followed by a common letter differ significantly (P<0.05)

The results of the fourth experiment were as follows: · Diphenamid had no effect on yield, population, or vigor. · Bromoxynil and methabenzthiazuron produced yields and populations similar to the control treatments despite the observed effect on crop vigor. · Bifenox and prometryn both caused serious crop damage. Grichar et al. (2001) cited Bennett (1989) and Eagleton et al. (1987) that fluazifop and sethoxydim were effective for grass control and were safe on sesame. Martin (1995) reported that metolachlor adequately controlled weeds but caused unacceptable crop injury. [Note that despite this assessment, most farmers and researchers in Australia use metolachlor as a PRE.] In the Northern Territories, in a grower's guide M. Bennett (1998) stated, "Where sesame is rotated with a cereal, there can be mutual benefits in weed control. Broadleaf weeds can be readily controlled in the cereal crop using selective herbicides, such as atrazine, 2,4-D, greatly reducing the risk of broadleaf weeds in the subsequent sesame crop. Similarly, grass weeds which are difficult to control in the cereal crop can be fairly easily controlled in a conventionally tilled sesame crop using PRE herbicides such as Treflan (trifluralin), Dual (metolachlor), and Stomp (pendimethalin). Eptam (EPTC) has also been used as a PRE herbicide for some broadleaf weeds." In South Burnett, a grower guide (Sapin et al. 2000) stated that PRE herbicides which are used overseas and successfully in trials in Australia are trifluralin (Treflan), metolachlor (Dual), diuron (Karmex), and linuron (Lorox). Sesame is susceptible to, but will tolerate, the grass killing herbicides ­ fluazifop (Fusilade), sethoxydim (Poast, Sertin), and haloxyfop (Verdict), but none of these are registered in Australia. Sesame will not tolerate ­ Caparol (prometryn), Roundup

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(glyphosate), 2,4-D, atrazine, nor paraquat. Residual carry-over of herbicides will also affect sesame, especially those of the sulfonylurea group of herbicides which are used in wheat and barley." O'Shanesy (2000) paralleled the above statements and in her production cost analysis showed the farmers using Dual and glyphosate with the glyphosate being used to knock down weeds prior to planting. M. Bennett (2003, pers. commun.): "We have no approved herbicides for sesame and need `minor crop' usage approval from the relevant authority. Dual (metolachlor) works well on our sandy clay loams, I like Stomp (pendimethalin) and we use Verdict (haloxyfop), Sertin (sethoxydim) and Fusilade (fluazifop-P) in research situation. Stomp gives us protection against pigweed which is a big bonus." M. Bennett (2007, pers. commun.): "We use Dual Gold (metolachlor) at 1/ha; we try and combine this with narrow row spacing, 32-36cm for conventionally prepared land and 50cm for zero till prepared land, (yes even in a mulch situation, 3-6t/ha) hoping for rainfall to incorporate. I also like Stomp 330EC (pendimethalin) at ~1L/ha, also hoping for rainfall to incorporate. In our trials we use irrigation within 24hrs. If grass weeds become a problem post emerge we use Verdict (haloxyfop) or Sertin (sethoxydim) or Fusilade (fluazifop-P) at recommended rates." Jim Barnes (2007, pers. commun.) stated that "PRE use of Dual (metolachlor) and Treflan (trifluralin) were OK but in our environment both require incorporation which can be difficult. Some of our farmers were zero till farmers so incorporation was not possible, and Dual is unreliable unless you can guarantee follow up rain when applied post planting. My observations were that just about any POST grass killing herbicides were OK (we did not try them all but fluazifop and haloxyfop were OK) although others I have heard about being used. Most of these herbicides are only active against grasses anyway so should be OK. POST broadleaf weed control remains the major issue in our environment. This has not been solved. One farmer subsequently growing sorghum following sesame said that using Starane (Fluroxypyr) in sorghum did not kill the volunteer sesame. However I was not able to follow this up and knowing Starane I would be very doubtful, but stranger things have happened in this area. Until the herbicide situation is sorted I do not believe sesame will be a major crop anywhere in Australia. Farms that are clean or have only grass weeds would be fine, but there are not too many of them around." In the Northern Territories, M. Bennett (2007) stated that the research had concentrated on summer grass control. Dual (metolachlor) and Treflan (trifluralin) applied at low rates (1.0 L/ha) on soils where sand content is less than 50 to 70% suppressed grass weed development with minimal reduction to sesame plant numbers. Since 1995 herbicide research has evaluated diuron, linuron, and Lontrel (clopyralid). Low rates of chemical applied PRE show promise but require further evaluation. He also reports that other oilseed herbicides will be tested in the near future to include: Eptam (EPTC), Cotogard (fluometuron + prometryn), Zoliar DF (norflurazon), pendimethalin (Stomp), prometryn (Gesagard), and several brands of trifluralin. BRAZIL In Paraiba, Beltrao et al. (1991) found that on a non-calcerous brown soil, seeds yield of sesame (cv. Seridio I and cv. Inamar) averaged 672 kg/ha in a year with above average rainfall. The use of fertilizer (30-30-0) increased seed yields by 45%. Weed control with 1 kg/ha diuron also enhanced seed production but mechanical weeding combined with fertilizer applications increased weed competition.

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In Paraiba, Viera et al. (1998) tested the efficacy of mixtures of diuron (at 0.75, 1.0 and 1.25 kg/ha) with pendimethalin (1.25 kg/ha) and alachlor (1.44 kg/ha) as PRE herbicides, during 1997. The main weed species were: Euphorbia hirta, Portuluca oleracea, Boerhavia diffusa, Bidens pilosa, Amaranthus spinosa, Ipomaea aegyptia, Cenchrus echinatus, Eleusine indica and Aristida palens. After 15 days, significantly greater phytotoxicity was observed following treatment with the highest dose of diuron plus pendimethalin (12.5%) and alachlor (21.25%). Control ranged from 97 to 99% after 30 days and from 96 to 98% after 60 days. There were no significant differences for the height of the 1st fruiting branch, the number of fruits per plant, and the yield between the different treatments and mowing. BULGARIA Lyubenov and Kostadinov (1970) conducted trials in 1969 in Bulgaria with sesame sown on chernozem smolnitsa soil on 29 May. Application of 4 kg/ha Lasso (alachlor) or mixtures of 4 kg/ha Patoran (metobromuron [OP]) and 3 kg/ha Afalon (linuron) with 3 kg/ha Lasso or 5 kg/ha Ramrod (propachlor) on 29-30 May gave effective control of weeds and increased seed yields and seed oil content. Betanal (phenmedipham) was tried as a POST herbicide and found it toxic to sesame. In Sadoyo, Georgiev (1980) concluded that on the basis of trials between 1974 and 1979, suitable herbicides for weed control in sesame included: Agriflan (trifluralin) at 2 l/ha and Pregard (profluralin) at 2 l/ha, both applied PPI to a depth of 8 to 10 cm; and Patoran (metobromuron [OP]) at 2 kg/ha and Kotoran (fluometuron) at 1 kg/ha applied up to 2 days after sowing to control annual broadleaved weeds. The quality and fat content of sesame seeds were not adversely affected by these treatments. Yields were increased by up to 17.5% compared with an untreated control. COSTA RICA A grower guide (Anon 2007d) recommends using one PRE application of fluometron (Cotoran 80% PM at 2 kg/ha) or trifluralin (Treflan at 2 l/ha). EGYPT In Giza, Hussien et al. (1983) summarized three years of experiments in 1978, 1979, and 1980. They studied nitralin [OP] and trifluralin PPI, and chloramben [OP], fluorodifen [OP], metolachlor, Galex (metolachlor + metobromuron [OP]), and linuron PRE. Two checks were used ­ one hand-hoed and the other with weeds. The major annual broad-leaved weeds were Amaranthus retroflexus, Corchorus olitorius, Datura stramonium, Euphorbia prunifolia, Gynadropsis gyandra, Portulaca oleracea, Solanum nigrum, and Xanthium spinosum. The major grass weeds were Echinochloa colonum, Digitaria sanguinalis and Dinebra retroflexa. Linuron, chloramben, Galex, and fluorodifen were good on annual broadleaves while trifluralin, nitralin, metolachlor, and Galex showed superiority in controlling annual grasses. The most harmful treatments in descending order were nitralin at 2.7 and 1.8 kg/ha, trifluralin at 1.6 kg/ha, chloramben at 0.87 kg/ha and fluoradifen at 3.24 kg/ha. Galex and linuron at 1.8 kg/ha as well as chloramben at 0.87 kg/ha provided significant increases in seed yield/ha by 80, 60, and 57%, respectively as compared to the unweeded check. Metolachlor at 1.2 kg/ha, chloramben at 0.58 kg/ha, fluorodifen at 3.24 kg/ha, and trifluralin at 1.6 kg/ha produced an increase of 45, 38, 44, and 45%, respectively as compared to the unweeded check. Increase in seed yield by handhoeing was about 30% compared to the unweeded check. Seed oil content of sesame was not

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affected by the weed control treatments. Higher protein content was achieved with nitralin at 1.8 and 2.7 kg/ha and Galex at 1.8 kg/ha. Ibrahim et al. (1988) studied the effect of 5 herbicides applied alone or in tank mixtures or hoeing on sesame crops infested with Echinochloa colonum, Dinebra retroflexa, Emex spinosa, Sida alba, Amaranthus lividus, Portulaca oleracea and Xanthium strumarium in 2 field trials at Shandaweel in 1984-85. Treatments included 2.30 kg/ha alachlor, 2.04kg/ha pendimethalin, 1.2 kg/ha linuron, 0.96 kg/ha diuron, and 1.92 kg/ha prometryn applied PRE individually, or as tank mixtures of alachlor or pendimethalin with the other herbicides. Pendimethalin alone or with linuron or diuron gave excellent control of grass weeds, while linuron or diuron alone or mixed with pendimethalin effectively controlled broadleaved weeds. The best control of annual weeds, high seed yields, and yield components resulted from treatment with pendimethalin alone or in tank mixtures with linuron or diuron. EL SALVADOR A growers guide (Anon 2007c) recommends 2.8 l/ha of Lasso (alachlor) or 1.4 l/ha of metolachlor. ETHIOPIA Moore (1973a) evaluated herbicides for use in sesame grown on a dark brown sandy clay loam under irrigation at Melka Werer. Prometryn applied PRE gave the best overall results. At 1 kg/ha, it controlled all weeds present except Cyperus spp. and Lactuca taraxifolia and persisted for 54 days. At 1.85 kg/ha persistence was extended to 105 days but some crop damage occurred. EPTC at 1.8 kg and 3.9 kg/ha PPI was active against Cyperus spp. but selectivity was not adequate. The performance of fluorodifen (2.2 kg and 3kg/ha) PRE was unsatisfactory due possibly to heavy irrigation which followed the application. Alachlor (1.6 kg and 2.75 kg/ha) PRE was the safest of the herbicides tested but residual activity was poor. Moore (1973b) carried out a trial in the higher rainfall area at Setit Humera where irrigation was not necessary. Trifluralin at 0.75 kg and 1.4 kg/ha PPI and alachlor at 2.9 kg/ha applied PRE gave the highest yields of sesame. EPTC PPI and fluorodifen PRE both caused substantial damage to sesame seedlings. Prometryn at 2.2 kg/ha completely eliminated the crop (in contrast to the result obtained at Melka Werer) suggesting that this herbicide is safe only under irrigation. Moore (1974) experimented in (a) irrigated trials at Melka Werer and (b) rain-fed trials at Homera in 1972-3 with up to 11 herbicides applied to sesame. Prometryn gave the most consisted weed control and seed yields (up to 0.57 t/ha) in (a), but hand weeding 2 or 3 times gave yields of 0.52-0.85 t. In (b) in 1972, alachlor and trifluralin gave good weed control with only slight crop damage and yields of 0.62 t/ha; hand weeding gave yields of 0.7 t/ha. EPTC, fluorodifen, prometryn, and diuron caused serious crop damage at the rates tested. Zewdie (1994 applied four herbicides applied PRE and POST on sesame (Var Mahedo-80) during the 1991 and 1992 crop seasons to select appropriate herbicides for weed control in irrigated sesame. The results indicated that, next to hand weeding, at 30-35 days after crop emergence, the herbicide metolachlor (at 2.51 product/ha) was most effective against both grass and broadleaf weeds and resulted in a significant increase in sesame seed yield HONDURAS

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In a grower handbook (Anon 2002), the use of PRE herbicides such as alachlor (Lasso) and trifluralin (Treflan) has proved to be very efficient in the control of weeds in sesame. INDIA Weiss (1971) cites Mani (1961) that sesone [OP] gave promising results for broadleaf weeds but not for perennial monocots. Rates of 1.4 and 2.8 kg/ha were applied and the highest yields were obtained with the 1.4 rate which was not significantly higher than the hand cleaned plots. The 2.8 rate was slightly phytotoxic and caused abnormal proliferation of the tap-root. In Sumerpur, Brar (1979) cited Anon (1977) that of the three herbicides tested (sirmate, nitrofen [OP], and alachlor), alachlor at 2.0 kg/ha gave the best results but weeding was still more economical and effective in weed control. Subramanian and Sankaran (1977) carried out field experiments in 1975 in summer and during kharif to study the efficiency of alachlor, fluometuron and dichlormate. In summer 1975, alachlor at 1.5 kg/ha gave a significantly higher yield (613 kg/ha) than the rest of the treatments. During kharif alachlor at 1.75 kg/ha was again significantly better (473 kg/ha) than other treatments. Alachlor at 1.75 kg/ha in combination with 30kg N /ha gave the maximum net income and also the highest return per rupee invested on weed control. Schrodter and Rawson (1984) cited Guar and Tomar (1978) who found that diphenamid [OP] at 4.5 kg/ha or alachlor at 2.2 kg/ha applied to previously hand weeded plots gave the highest yield. Shukla (1984) found that a spray of 1 l/ha of propanil (Stam-F34) before sowing sesame gave effective control of weeds and resulted in seed yields of 127.5 kg/ha, compared with 132.5 kg on hand weeded plots and 72.5 kg without weed control. Application of nitrofen [OP] or Stomp (pendimethalin) was toxic to the crop. Ghosh and Mukhopadhyay (1980) carried out field experiments during the kharif season of 1979 that showed that fluchloralin [OP] at 0.72 kg/ha applied PRE (1 day after sowing) effectively controlled weeds and increased the seed yield of the crop to a level comparable to that obtained on weed-free controls. No advantage was gained by hand-weeding the fluchloralin treated plots 30 days after sowing. Higher rates of fluchloralin injured the crop, while nitrofen [OP] at 1 and 2 kg/ha PRE, though effective against weeds, was also not well tolerated by sesame. In Coimbatore, Subramanian and Sankaran (1981) conducted field experiments for 2 seasons to study the effect of PRE herbicides in controlling Trianthema portulacastrum and Cyperus rotundus in sesame. Sesame was given fluometuron at 0.25-1.75 kg/ha PRE in the summer season and alachlor at 1.5-1.75 kg/ha or dichlormate at 1.25-1.5 kg/ha PRE in the monsoon season. Alachlor at 1.75 kg/ha effectively controlled T. portulacastrum and C. rotundus in both seasons. Dry matter production and NPK removal by the weeds were lower with alachlor than with fluometuron or dichlormate and were similar to those with hand weeding. Bansode and Shelke (1991) assessed six weed control treatments (an unweeded control, hand weeding (HW) + hoeing 3 weeks after sowing (WAS), PPI of 0.68 or 1.12 l/ha fluchloralin [OP] and PRE alachlor at 0.75 or 1.5 l/ha in field trials during the kharif of 1988 with sesame (cv. Punjab-1 and T-85). Results indicated that sesame cv. Punjab 1 outyielded (447 kg/ha) the cv. T85 (247 kg). PRE alachlor applied to cv. Punjab-1 combined with HW + hoeing gave highest yields (689 kg) compared to HW + hoeing alone (583 kg) and all other treatments. Lowest yield (75 kg) was obtained with cv. T-85 and fluchloralin which was phytotoxic to this cultivar.

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Appendix 1. Sesame herbicide research by country

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In Madhya Pradesh, Sootrakar et al. (1995) conducted a field experiment in 1991-92. Hand weeding 25, 40 and 55 days after sowing (DAS) produced the highest mean seed yield of 0.77 t/ha, followed by 0.69 t obtained with PPI of 2 l/ha fluchloralin [OP] + hand weeding 25 DAS. The application of 2 l/ha fluchloralin PPI alone produced a mean yield of 0.66 t and the highest net return. In Madhya Pradesh, Chauhan and Gurjar (1998) carried out a field experiment during 1991 and 1992 to study mechanical and chemical weed control in sesame on sandy loam soil. Mechanical and chemical treatments significantly reduced dry matter production by weeds compared with the untreated control. Three hand-weedings (20, 40 and 60 days after sowing) and pre-sowing application of 0.75 kg/ha Basalin (fluchloralin [OP]) both gave highest yield, followed 2 handweeding at 20 and 40 days.. In Uttar Pradesh, Om et al. (2001) investigated the effects of N fertilizer application and weed (Cyperus rotundus, Cynodon dactylon, Phyllanthus niruri and Digera muricata) control measures on sesame during 1995 and 1996. Treatments consisted of N levels, i.e. 0, 30, 60 and 90 kg/ha, and weed control treatments, i.e. weedy control, hand weeding 3 weeks after sowing, PRE application of oxyfluorfen (0.15 kg/ha) + hand weeding, PREPLANT application of fluchloralin [OP] (1.0 kg/ha) + hand weeding, PRE application of alachlor at 1.0 kg/ha and PRE application of alachlor (1.0 kg/ha) + hand weeding. N fertilizer rate did not significantly affect the weed population. For the crop in both years, the application of 90 kg N/ha resulted in the highest number of capsules per plant, seeds per capsule, 1000 seed weight, seed yield, straw yield and harvest index. Aside from exhibiting the highest weed-killing efficiency, PREPLANT application of fluchloralin + hand weeding recorded the highest values for seed yield and most yieldcontributing characters. In Haryana, Punia et al. (2001) conducted an experiment on sandy loam soil during kharif 1999 and 2000, to investigate the efficacy of trifluralin, pendimethalin and fluchloralin [OP] against weeds in sesame cv. HY-1. Sixteen treatments compromising trifluralin and pendimethalin each at 1.0, 1.25 and 1.5 kg/ha; fluchloralin [OP] at 0.75, 1.0 and 1.25 kg/ha integration of each of these herbicides with one hoeing at 4 weeks after sowing (WAS), 2 hoeings at 3 and 6 WAS and one hoeing at 4 WAS untreated; and weed free control. Trifluralin and fluchloralin PPI in 2-3 cm top soil before sowing and pendimethalin PRE. The dominant weeds in the experimental area were Echinochloa colonum, Dactyloctenium aegyptium and Trianthema portulacastrum. On an average, season long weed competition caused 61% reduction in seed yield. Two hoeings at 3 and 6 WAS, integration of either fluchloralin, pendimethalin or trifluralin at 1.0 kg/ha with one hoeing at 4 WAS were significantly better in terms of weed control efficiency and seed yield compared to one hoeing at 4 WAS or herbicides used alone. In Rajasthan, Dungarwal et al. (2003) conducted a field experiment during the kharif seasons of 1997 and 1998 to evaluate the relative efficacy of fluchloralin [OP], pendimethalin, trifluralin and alachlor herbicides applied alone or in combination with one hoeing at four weeks after sowing (WAS) to control weeds in sesame (cv. TC 25). On average, season-long weed competition caused 50% reduction in seed yield. Integration of herbicides, fluchloralin, pendimethalin and trifluralin at 1.0 kg/ha or at 2.0 kg/ha with one hoeing at 4 WAS was more effective when assessed in terms of weed control efficiency and seed yield compared to their single application. Among the herbicides, the PRE application of alachlor at 2.0 kg/ha combined with one hoeing at 4 WAS registered the highest weed control efficiency which enhanced yield attributes leading to higher seed yield (530 kg/ ha) and net return (Rs. 4275/ha). This treatment was at par with fluchloralin applied in conjunction with one hoeing.

Use only herbicides approved and tested in your area

Appendix 1. Sesame herbicide research by country

Page 11

In Rajasthan, Chandawat et al. (2004) conducted a field experiment to look at the efficacy of hand weeding 20 and/or 30 days after sowing (DAS), 1.5 kg/ha of alachlor PRE alone or in combination with hand weeding 30 DAS, PPI of 2.0 kg/ha alachlor alone or in combination with hand weeding 30 DAS, 0.5 kg/ha pendimethalin applied alone or in combination with hand weeding 30 DAS and 2 kg/ha metolachlor applied alone or in combination with hand weeding 30 DAS. Amaranthus spinosus, Cenchrus biflorus, Trianthema portulacastrum, Boerhavia diffusa, Cynodon dactylon, Tribulus terrestris, Euphorbia microphylla, Phyllanthus niruri, Digera arvensis, Corchorus tridens, Heliotropium ovalifolium, Portulaca oleracea and Celosia argentea were the dominant weeds. Weed control efficiency was highest (88%) with the PRE 1.5 kg/ha alachlor and 0.5 kg/ha pendimethalin in combination with hand weeding 30 DAS. Plant height was highest with the application of alachlor in combination with hand weeding. Application of 2 kg/ha alachlor in combination with hand weeding resulted in the highest number of primary branches per plant (45), pooled seed yield (713 kg/ha), net returns (10736 kg/ha), and benefit cost ratio (2.17). In Rajasthan, Yadav (2004) conducted a field experiment during the 1998 and 1999 kharif seasons on sesame (cv. RT-46) to determine a suitable integrated method for weed control. The treatments comprised: weedy control; one hand-weeding (HW) at 20 days after sowing (DAS); 2 HW at 20 and 40 DAS; PPI of 0.5 kg/ha fluchloralin [OP]; PPI of 0.75 kg/ha fluchloralin + HW at 40 DAS ; PPI of 0.5 kg fluchloralin /ha + HW at 40 DAS; PPI 0.75 kg/ha fluchloralin; PRE of 0.75 kg pendimethalin/ha; PRE of 0.5 kg/ha pendimethalin + HW at 40 DAS; and PRE of 0.75 kg/ha pendimethalin + HW at 40 DAS. The weedy control plot was heavily invaded by Amaranthus viridis, Phyllanthus niruri, Trianthema monogyna (Trianthema portulacastrum), Cynodon dactylon, Digera arvensis and Celosia orgentia (Celosia argentea). The lowest weed dry matter and highest weed control efficiency, number of capsules per plant, pooled mean seed yield, gross returns, net returns, and incremental benefit cost ratio were obtained with PPI of 0.5 kgha fluchloralin + HW at 40 DAS treatment. In Himachal Pradesh, Anil and Thakur (2005) studied the effects of sowing method (line sowing or broadcasting) and weed control methods (hand weeding at 20 and 40 days after sowing or DAS, and 1.5 kg/ha alachlor with or without hand weeding once) on the productivity of sesame (cv. Brajeshwari) monocropping or sesame + black gram (UG 218) were studied during the kharif of 2003 and 2004. The dominant weeds in the area were Panicum dichotomiflorum, Echinochloa colonum, E. crus-galli, Cynodon dactylon, Cyperus iria, and Cyperus difformis. Intercropping sesame with black gram reduced the weed density (by 53.3%) and dry matter accumulation (by 51.3%) over sesame monocropping. Line sowing significantly reduced the weed density by (19.8%) over broadcasting. Alachlor + hand weeding recorded the lowest weed density (21.4/m2) and dry matter (8.5 g/m2). Hand weeding twice reduced the weed density and dry matter accumulation by 57.5 and 60.4%, respectively, over the control. The seed yield of sesame was higher (by 31.6%) under monocropping. Line sowing increased the yield by 10.6% over broadcasting. The highest sesame seed yields were obtained with 1.5 kg alachlor/ha singly (260 kg/ha) or in combination with hand weeding (284 kg/ha). Intercropping sesame with black gram increased the total productivity by 197% over monocropping. Alachlor with or without hand weeding resulted in the greatest total productivity. The highest net returns were obtained with sesame + black gram (18,814 rupees/ha), broadcasting (11,018 rupees/ha) and alachlor + hand weeding (12,984 rupees/ha). In Tamil Nadu, Gnanavel and Anbhazhagan (2006) conducted a field experiment in summer 2002 to evaluate the efficacy of different PRE herbicides and herbicide along with hand weeding (HW) in controlling weeds in irrigated sesame cv. TMV 5. The treatments comprised a control, HW

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Appendix 1. Sesame herbicide research by country

Page 12

twice at 20 and 40 days after sowing (DAS), one HW at 30 DAS, 1.5 kg/ha fluchloralin, 1.0 kg/ha fluchloralin + HW at 30 DAS, 1.5 kg/ha pendimethalin, 1.0kg/ha pendimethalin + HW at 30 DAS, 0.25 kg/ha oxyfluorfen , 0.15 kg/ha oxyfluorfen + HW at 30 DAS, 2.0 kg/ha alachlor, and 1.0 kg/ha alachlor + HW at 30 DAS. The application of 0.15 kg/ha oxyfluorfen with one HW at 30 DAS was significantly better in terms of weed control index (92.7%) and seed yield (0.92 t/ha) compared to HW twice or herbicide used alone. ISRAEL Graph et al. (1985) showed that PPI of trifluralin 0.125-0.188 kg/ha was selective to sesame when the crop was sown on relatively warm soil. Early sowing of trifluralin resulted in inhibited root growth due to cold soil, retardation, and crop damage. PPI application of dinitramine and napropamide also caused severe crop damage. PRE treatment with 1.0-2.0 kg/ha of alachlor was selective to sesame but caused damage when applied with a PPI trifluralin treatment. 3.0 kg/ha diphenamid [OP] temporarily retarded crop growth and various substituted ureas sprayed PRE or POST caused crop damage. KOREA In a research summary, Lee (1986) recommended Pamid WD (napropamide) and Alar (alachlor). Kim et al. (1986) conducted field trials in the sesame-producing uplands of Korea, to study the herbicide efficacy and phytotoxicity in crops grown under polyethylene film. Portulaca oleracea, Digitaria sanguinalis and Amaranthus mangostanus were the major problem weeds. Most effective overall weed control was obtained using 1.27 kg/ha pendimethalin, 0.67 kg/ha trifluralin or 0.12 kg/ha Codal (metolachlor + prometryn). 3 l/ha napropamide or 1.5 l/ha alachlor gave sesame yields equivalent to that obtained with manual weed control, whereas the other herbicides caused crop damage and yield reductions. MEXICO In Michoacan, a grower handbook (Anon 2007a) recommends the following PRE treatments:

Common name of ingredient Alachlor Alachlor + Linuron Alachlor + Diuron Commercial name Lasso Alanox Lasso afalon Alanox + Linorox Lasso karmex Alanox + Diurol Herbilaz crisuron Dose/ha 2.5 lt 3.0 lt 1.0 l + 0.5 kg 1.5 l + 0.5 kg 2.0 l + 0.5 kg

They recommend higher doses for clay soils and lighter for sandy soils. In all cases should be dissolved in 250 to 300 l of water and applied immediately after planting. NICARAGUA Soto and Silva (1987) conducted plot trials at 2 sites in Nicaragua. C.v. China Roja sown in August was treated immediately with 1.4 or 2.1 l/ha Lorox-L (linuron), 1.4 or 2.9 l/ha Cyperal (benfuresate), 1.4 or 2.1 l/ha Dual (metolachlor), or 1.4 or 2.1 l/ha Prowl (pendimethalin). Assessment of weed and crop populations 15, 30, and 45 days after treatment showed that Prowl and higher rates of Cyperal were phototoxic with 2.1 l/ha Prowl reducing seed yield 129 days

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Appendix 1. Sesame herbicide research by country

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after sowing to 0.283 t/ha compared with 1.089 t in the untreated stand and 2.224 t in the stand treated with 2.1 l/ha Dual. Of the herbicides tested, Dual gave the best control of grass weeds and Lorox-L gave best control of broadleaved weeds present; neither damaged the sesame; recommended rate of application for both herbicides was 2.1 1/ ha. NIGERIA In a survey of agricultural crops (Anon 2004), it states, "The use of Galex (metolachlor + metobromuron [OP]) as a PRE and Fusilade (fluazifop) as a POST for weed control were reported by two benniseed farmer cooperatives." PAKISTAN In a grower guide, Panhwar (2005) recommends alachlor 1.75 kg/ha, fluchloralin [OP] 0.75 kg/ha, or pendimethalin 1.0 kg/ha. In a grower guide (Anon 2007b) it states, "During the first few weeks after emergence, the sesame seedlings are very sensitive to weeds, hence an effective weed control measure is vital during this period. Different types of perennial grasses, like Khabbal, Baroo and annual broad leaved weeds like Cholai, Hazardani, Bakhra and Tandlla compete the crop in rainfed as well as irrigated areas. These weeds can easily be controlled by adopting cultural methods (crop rotation and tillage practices) and chemical weed methods depending on weed species, degree of infestation and weather pattern etc. However PRE herbicide (Stomp 330 E) @ 1.48 ai kg/ha can be used before germination and is very effective in controlling wide range of grasses and broad leaf weeds." SOMALIA Warfa and Noor (1978) conducted pot trials in 1976 in soil without or containing Gesaprim (atrazine) residues. Sesame was sown in the pots to assess the sensitivity to the residue. In soil treated 6 months earlier with Gesaprim there was no growth by sesame. In soil treated 8 months earlier with Gesaprim there was no significant difference in seedling dry matter between treated and untreated soils. Malik and Ramzan (1992) conducted field studies in Somalia during April-June and OctoberDecember 1989, to examine the efficacy and yield of PRE Stomp 330E (pendimethalin) at 3.7 l/ha, POST herbicides Fusilade 25EC (fluazifop-P) at 3.7 l/ha, and Gramoxone 20EC (paraquat) at 1.5 l/ha as compared to hand weeding for the control of weeds infesting sesame. Greatest weed control was obtained using Stomp (86.04%), followed by hand weeding (84.97%) and Gramoxone (81.34%). Stomp 330E treated plots gave a significantly higher seed yield (5.08 t/ha) compared to the untreated control (3.06 t/ha), and did not produce any phytotoxic effects. SRI LANKA Weiss (1971) cites Anon (1960) that eptam (EPTC) gave promising results. Weiss (1971) cites Appendurai (1967) who found that diuron applied at a rate of 0.6 to 0.8 kg/ha gave effective control of weeds with no significant reduction in yield. THAILAND

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Appendix 1. Sesame herbicide research by country

Page 14

A field guide (Anon 1997) states that hand weeding is practiced twice at 15 and 25 days after emergence. The PRE herbicides metolachlor (1-1.25 l/ha) or alachlor (1.2-1.5 l/ha) is also recommended in case of labor shortage. W. Wongyai (2007, pers. commun.) applied Frontier (dimethenamid) 2 weeks before planting and PRE in her nurseries. It gave the good results for two years in the dry season, planting in December 2005 and in August 2005. But in the wet growing season of April it killed almost all sesame lines. For the wet growing season in February 2007, she applied alachlor, and applied Whip 85 (fenoxaprop) in March planting PRE. The latter is used in rice, and she will no longer use it on sesame. Some farmers apply Stomp (pendimethalin) POST. In her nurseries she has applied it POST for grass control. TRINIDAD Weiss (1971) cites L. Kasasian (1967, 1968) that trials over several years showed norea to be a highly effective herbicide in sesame. In a PRE trial, norea at 6.6 kg/ha outyielded the control, but a 4.4 and 2.2 kg/ha was decreasingly effective. A combination of 3.3 kg/ha norea plus 3.3 kg/ha diphenamid was also less effective than 7 kg/ha of norea. He also provides the following table with work on other herbicides.

Herbicide Weed-free control Diphenamid a Monolinuron Norea a Monolinuron + Diphenamid a

a

Rate (kg/ha) 4.5 9.0 1.1 2.2 2.2 4.5 1.1 2.2

Percent yield 100 97 79 89 53 88 74 61

Out of production

UNITED STATES Culp and McWhorter (1965) cited Tocquigny and Livingston (1953) that PRE monuron and sesone were promising for use in sesame. POT OTT MCPA (2,4D), naptalam (NPA), a mixture of NPA and NPA imide, and endothal caused slight to severe stunting. However, most of the plants except for those treated with endothal essentially overcame the stunted condition before harvest. In Mississippi, Culp and McWhorter (1965) cited Culp and Holstun (1958) that chlorpropham (CIPC) at 4 and 8 lb/ac, diuron at 0.75 and 1.5 lb/ac, and allidochlor (CDAA) at 3 and 6 lbs/ac gave adequate weed control without apparent crop injury. Sesame was severely injured by naptalam (NPA) at 2 and 4 lb/ac, and simazine at 2 and 4 lb/ac. In Mississippi, Culp and McWhorter (1965) cited Culp and McWhorter (1959) that diuron at 0.9 lb/a, and allidochlor (CDAA) at 6 lb/ac caused chlorosis and stand reductions. Diuron at 0.7 lb/ac and allidochlor at 3 lb/ac were non-toxic. In Virginia, Culp and McWhorter (1965) cited Chappell (1959) that chlorpropham (CIPC) at 6 lb/ac caused little or no crop injury to sesame grown.

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Appendix 1. Sesame herbicide research by country

Page 15

Culp and McWhorter (1965) cited Santelmann et al. (1963) who found diphenamid [OP] at 3 lb/ac and EPTC at 2 lb/ac were safe applied one day after planting. Slight phytotoxicity and yield reduction occurred with chlorthal-dimethyl (DCPA) and linuron at low rates, but linuron at 2 lbs/ac, Amiben (chloramben [OP]) at 4 lb/ac, and DCPA at 12 lb/ac reduced yields. In South Carolina, Culp and McWhorter (1965) cited Martin and Crawford (1963) who reported that chlorpropham (CIPC) had been used successfully for a number of years as a broadcast PRE treatment on sesame. Six additional PRE herbicides chlorthal-dimethyl (DCPA), norea [OP], sulfonamide and 2,4D caused slight to severe damage, but when they were tried at lower rates none caused visible plant injury and all gave weed control essentially equivalent to that obtained with CIPC. The tests with dichlobenil at 4 lb/ac killed or damaged sesame in all tests. In South Carolina, Weiss (1971) cited Martin (1963, 1964) who reported that trifluralin at 2.5 lb/ac killed or damaged sesame in all tests, but that at 1.1 to 1.6 kg/ha trifluralin was effective and non-toxic. Monuron [OP] at 0.18 and 0.40 kg/ha PRE gave good control of weeds, with no injury to sesame at the lower rate and no significant reduction in yield In Mississippi, Culp and McWhorter (1965) performed several experiments over 3 years. In the greenhouse 13 herbicides were tried at different rates on sesame and four different weeds. They concluded that although pebulate (PEBC) and chlorpropham (CIPC) both provided good weed control and had 15% or less injury on the sesame that CIPC was chosen for further experiments because it could be readily applied with conventional farm equipment. In a 1961 experiment CIPC was used at different rates with the following results.

Rate Weed rating a Sesame rating a lb/ac 6 90 2 8 95 11 10 95 4 12 98 2 14 98 2 16 100 11 32 100 8 0 3 6 a 0 = no injury, 100 = complete kill Yield lbs/ac 790 bc 880 ab 830 abc 900 ab 600 c 820 abc 670 bc 1060 a

All rates provided excellent annual weed control with essentially no visible injury to sesame, even when applied at 32 lb/ac. Yields on all treated plots were lower than in the check plots. The reason for lack of correlation between yields and rates of herbicide is not clear. Some other factors must have caused these differences. The rainfall was adequate, but the stand was probably too thick for maximum production. Also the experimental area was more variable than desirable. In 1963 CIPC at different rates was tried on 3 planting dates with the following results:

Rate lb/ac 6 9 12 0

a

May 3 78 85 93 0

Weed rating a May 15 85 99 99 0

Jun 1 83 89 94 0 Average

May 15 1700 1740 1720 1710 1720

Yield lbs/ac Jun 1 1220 1210 1110 1120 1170

Average 1460 1480 1420 1420 1440

0 = no injury, 100 = complete kill

They concluded that CIPC was highly selective for PRE use in sesame. Optimum rates are similar to those currently recommended for weed control in cotton and other crops.

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Appendix 1. Sesame herbicide research by country

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In California, St Andre (1969) conducted PPI trials under furrow irrigation, planted 10 Jun. Variety was Baco planted at 2.5 lbs/ac. The stand counts were done 5 Jun and the ratings 10 Jun. Barley was broadcast in the trial area prior to bed shaping.

Herbicide Diphenamid d Prefar (bensulide) CIPC (chlorpropham) PPG-116 (chlorpropham) Amiben (chloramben d) Trefmid c (trifluralin + diphenamid d) Eptam (EPTC) EL-179 (isopropalin) Rate lb/ac 5.0 5.0 4.0 4.0 Stand count a Sesame Barley 62.0 51.6 15.6 16.6 9.3 11.3 0 0 Visual rating b Barley Sesame control injury 6.3 0 4.6 0 10.0 6.0 10.0 6.3

3.0 59.6 18.3 0 0 .25 + 40.3 5.0 5.6 5.6 4.0 3.0 39.3 9.6 5.3 2.6 1.0 38.0 11.3 2.3 4.3 2.0 37.0 12.6 5.0 4.6 R-12001 (carbothioate) 3.0 31.0 4.3 6.6 4.0 6.0 14.3 2.6 8.0 5.6 CP-53619 (EPTC) 2.0 53.3 24.0 0 0 4.0 37.3 15.6 3.3 2.0 Untreated --55.3 21.6 0 0 a Stand count values represent the average number of plants in 8 feet of row b Ratings based on 0-10 scale. 0 = no control or injury. 10 = perfect control or very severe injury. Injury rating reflects retardation and vigor in the growth of sesame.

c d

Trefmid includes 0.25 lb/ac trifluralin and 4.0 lb/ac of diphenamid.

Out of production

The materials that did no injury to the sesame (diphenamid, bensulide, chloramben and the low rate of EPTC) did not control the barley. The materials that controlled the barley (chlorpropham) injured the sesame. The rest had some control and some injury. In California, St Andre (1970a) conducted PPI trials under furrow irrigation, planted 14 May. Variety was 215 (semi-shattering). Evaluated 2 Jun. Barley was broadcast in the trial area prior to bed shaping, and mustard and Japanese millet were planted along with the sesame.

Herbicide Rate Sesame Grass lb/ac Diphenamid c 5.0 97.0 0 1.0 0.3 Prefar (bensulide) 5.0 65.0 0 1.3 1.3 Amiben (chloramben c) 4.0 55.0 4.0 1.3 63.6 CIPC (chlorpropham) 4.0 2.0 0 0 0 Lasso (alachlor) 2.0 85.6 0 0 0.6 4.0 54.0 0 0.6 0 Herban (norea c) 2.0 110.0 0 1.0 4.0 4.0 83.6 0 0 1.6 Kerb (pronamide) 1.0 1.3 0 0 0 2.0 0.6 0 0 0 Amiben (chloramben c) + 3.0 25.6 1.3 0 9.6 CIPC (chlorpropham) 2.0 Untreated --96.0 6.6 1.3 58.3 a Stand count values represent the average number of plants in 8 feet of row b Ratings based on 0-10 scale. 0 = no control or injury. 10 = perfect control or very severe injury. Injury rating reflects retardation and vigor in the growth of sesame. Stand count a Pigweed Mustard Visual rating b Weed Sesame control injury 9.8 3.0 8.6 2.3 1.0 2.0 10 9.3 10 3.3 10 3.3 9.5 0.3 10 4.0 10 9.6 10 10 8.6 5.0 0 0

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Appendix 1. Sesame herbicide research by country

c

Page 17

Out of production

Pronamide and chloramben reduced sesame stands substantially. All of the herbicides had good weed control with chloramben, bensulide, norea low rate, and diphenamid having the least injury. Diphenamid, alachlor at a low rate, and norea had the least effect on the sesame stand, reasonable injury, and good weed control. In California, St Andre (1970b) conducted PPI (5-6.3 cm) trials under furrow irrigation, planted 25 Jun. Stand counts were done 14 Jul and the ratings 18 Jul. The barley was harvested, disked in, listed, and preirrigated. Herbicides were applied and incorporated in the same operation with planting.

Rate lb/ac Lasso (alachlor) 2.0 65.5 9.0 4.0 55.6 2.0 Herban (norea c) 1.5 87.5 12.3 3.0 53.0 6.6 CIPC (chlorpropham) 3.0 27.6 0.6 Diphenamid c 5.0 65.0 1.6 Tenoran 1.5 6.3 13.6 (chloroxuron c) 3.0 0.6 5.0 Diphenamid c + 3.0 66.3 4.0 Lasso (alachlor) 1.5 Prefar (bensulide) 6.0 83.0 3.6 8.6 0 Prefar (bensulide) + 3.0 77.0 7.0 7.6 0 Lasso (alachlor) 1.5 Untreated --81.0 14.0 1.6 0.6 a Stand count values represent the average number of plants in 8 feet of row b Ratings based on 0-10 scale. 0 = no control or injury. 10 = perfect control or very severe injury. Injury rating reflects retardation and vigor in the growth of sesame. c Out of production Herbicide Stand count a Sesame Barley Visual rating b Barley Sesame control injury 7.3 0 8.6 0 4.6 0 6.0 1.0 9.3 4.0 9.0 1.3 5.3 3.0 8.6 9.3 9.0 1.0

Alachlor, bensulide, and norea low rate, and diphenamid/alachlor were the best in terms of less stand reduction, sesame injury, and weed control. The chloroxuron and CIPC reduced the sesame stand substantially. In California, Fischer (1971) summarized the work that had been done since 1967 in the San Joaquin valley to include the results of St Andre (1969, 1970a, and 1970b). In that area the concept was to grow sesame double cropped after barley or other cereals and thus the emphasis was on controlling volunteer grasses. He summarized the results for the years as follows:

Trade name Alanap Amiben Balan CIPC Dacthal Dymid or Enide Eptam Herban Kerb Lasso Maloran Planavin Active ingredient Naptalam Chloramben a Benefin Chlorpropham Chorthal-dimethyl (DCPA) Diphenamid a EPTC Norea a Pronamide Alachlor C-6313 Nitralin a Lbs/ac evaluated 5.0 3.0/4.0 1.25 3.0/4.0 8.0 5.0/6.0 3.0 1.5/3.0 1.0/2.0 2.0/4.0 2.0/4.0 0.75/1.0 Sesame tolerance Poor Good Poor Poor Poor Good Poor Fair Poor Fair Fair Poor Barley control Poor Poor Erratic Good Erratic Good Good Poor Good Good Erratic Erratic

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Appendix 1. Sesame herbicide research by country

Page 18

Trade name Prefar Sindone Tenoran Treflan Trefmid Vernam C-10725 CP-53619 EL-179 MB-9057 PPG-116 R-12001 a Out of production

Active ingredient Bensulide Chloroxuron a Trifluralin Trifluralin + Diphenamid a Vernolate Diethylacetanilide Isopropaline Asulam Chlorpropham Carbothiote

Lbs/ac evaluated 4.0/6.0 2.0 1.5/3.0 0.75/1.5 0.25/4.0 on each 3.0 2.0 2.0/4.0 1.0/2.0 3.0 4.0 3.0/6.0

Sesame tolerance Good Poor Poor Poor Poor Poor Fair Fair Poor Good Poor Poor

Barley control Poor Poor Poor Erratic Good Good Poor Poor Erratic Poor Good Poor

Their overall evaluations were as follows: · Diphenamid effectively controlled volunteer barley and other annual weeds without adversely affecting sesame. · Bensulide was well tolerated by sesame but failed to adequately control volunteer barley and was also erratic in controlling broadleaf weeds. · Chlorpropham effectively controlled the barley but severely reduced the sesame stand when incorporated preplant. · Norea at 2 lbs/ac looked promising, but caused some stand reduction and growth retardation at 4 lbs/ac and did not provide effective control of volunteer barley. · Alachlor provided effective weed control and at 2 lbs/ac did not adversely affect the sesame but the stand was reduced at 4 lbs/ac. · Chloramben was well tolerated by sesame but failed to control the weeds when PPI. In California, St Andre (1973) conducted PPI trials under furrow irrigation, planted 15 May. Variety was 247 (nonshattering). Evaluated 14 Jun. Note that the stands are much lower than the other St Andre testing. Nonshattering (indehiscent) lines have much less vigor than semishattering or shattering lines.

Herbicide Dymid (diphenamid c) Prefar (bensulide) Lasso (alachlor) Devrinol (napropamide) Bolero (thiobencarb) Ronstar (oxadiazon) Probe (methazole) Amiben (chloramben c) Sencor (metribuzim) Prefar (bensulide) + Rate lb/ac 5.0 5.0 2.0 4.0 1.0 2.0 4.0 8.0 2.0 4.0 2.0 4.0 1.0 3.0 0.5 1.0 4.0 Sesame vigorb 10 10 9.3 9.5 9.0 6.5 8.5 6.3 9.3 10 9.8 8.0 9.8 10 7.8 7.3 9.0 Sesame 16.7 14.7 16.0 16.2 14.5 10.0 7.2 0.5 14.2 13.5 12.2 9.0 15.0 15.5 7.0 0.5 12.0 Stand count a Mustard Japanese millet 9.0 1.2 7.5 0 4.5 0 2.5 0 10.0 0.2 10.2 0.2 8.5 0.7 5.2 0.2 10.2 18.7 6.0 9.2 0 3.5 0 0 10.5 1.5 7.0 12.7 0.5 4.2 0 1.2 7.5 2.0 Pigweed 3 1 1 0 3 0 48 28 17 23 1 0 7 18 0 0 0

Use only herbicides approved and tested in your area

Appendix 1. Sesame herbicide research by country

Page 19

Herbicide

Rate Sesame Sesame Pigweed lb/ac vigorb Lasso (alachlor) 2.0 Destun (perfluidone c) 2.0 8.0 14.2 15.0 20.2 17 4.0 9.3 12.0 8.7 7.0 14 Untreated --10 12.2 7.5 5.5 23 a Stand count values represent the average number of plants in 8 feet of row in 4 replications except for the pigweed which was only present in the 3rd replication. b Vigor evaluation is based on a 0-10 scale with 0 = very poor vigor and 10 = vigorous growing plants. c Out of production

Stand count a Mustard Japanese millet

Thiobencarb and metribuzim reduced sesame stands substantially. Alachlor, bensulide, and dephenamid and the low rate of methazole had little stand reduction, little effect on vigor, and good weed control. The alachlor and metahzole low rate were the only herbicides that did little damage to the sesame and somewhat controlled the mustard. In California, St Andre (1974) conducted PPI (5-6.3 cm) trials under furrow irrigation, planted 28 May. Millet was seeded in the south half of each plot. Variety was Lucidi (shattering). Evaluated 13 Jul.

Herbicide Enide (diphenamid d) Prefar (bensulide) Lasso (alachlor) Rate lb/ac Sesame vigor b 6/28 7.5 8.7 8.2 7.0 4.5 2.0 5.0 4.0 9.0 8.5 4.5 Sesame vigor b 7/13 8.0 9.5 9.2 9.0 6.7 4.5 7.7 6.2 9.5 9.5 5.5 Percent stand a 6/28 91.2 95.0 95.0 78.7 56.2 23.7 56.2 15.7 95.0 96.2 68.7 Percent stand a 7/13 76.2 91.2 87.5 77.5 62.5 17.2 62.5 16.2 90.0 87.5 42.5 Weed control c 7/13 6.0 10.0 9.5 9.7 9.2 6.7 9.2 9.2 10.0 10.0 7.2

4.0 5.0 2.0 4.0 Probe (methazole) 2.0 4.0 Bay-NTN 6867 1.5 (amiprophosmethyl) 3.0 H-22234 (diethatyl) 2.0 4.0 Probe (methazole) + 2.0 HOE 23408 (diclofop) 2.0 4.0 1.7 5.0 8.7 9.5 8.0 2.0 1.0 9.0 8.2 95.0 87.5 --Devrinol (napropamide) + 4.0 Enide (diphenamid d) Devrinol (napropamide) + 1.0 2.7 6.0 30.0 17.5 9.7 Lasso (alachlor) 2.0 Enide (diphenamid d) + 4.0 6.2 7.5 72.5 72.5 10.0 Lasso (alachlor) 2.0 Untreated --9.0 9.2 93.7 90.0 4.2/3.7 a Stands are based on an estimated percentage. Note that the untreated stands are not 100%. b Vigor evaluation is based on a 0-10 scale with 0 = very poor vigor and 10 = vigorous growing plants. c Ratings based on 0-10 scale. 0 = no control. 10 = perfect control. d Out of production

It is difficult to evaluate individual herbicides when used in combinations because it is difficult to determine which half of the combination had more effect on the sesame and weeds. This is more of an exercise to eliminate herbicide candidates and combinations in which the following do not show promise: Diphenamid because of low weed control; methazole (plus combinations),

Use only herbicides approved and tested in your area

Appendix 1. Sesame herbicide research by country

Page 20

amiprophosmethyl, napropamide + alachlor, and diphenamid + alachlor because on effects of sesame stands and vigor. Bensulide and alachlor appear to be the best candidates. In California, St Andre (1978) conducted PPI trials (5-6.3 cm) under furrow irrigation, planted 22 May. Weeds present were barley, ground cherry, sowthistle, pigweed, and lambsquarter. Variety was Lucidi.

Herbicide Prefar (bensulide) Enide 90W (diphenamidc) Prefar (bensulide) + Enide 90W (diphenamidc) Dual (metolachlor) Lasso (alachlor) San 252 Rate lb/ac 6.0 4.0 6.0 4.0 4.0 2.0 2.0 2.0 4.0 2.0 4.0 2.0 0.5 2.0 Vigor 9.5 7.5 9.2 9.7 8.7 9.7 10 9.7 9.5

a

Grasses 6/13 3.7 5.0 9.0 6.2 6.0 6.2 1.7 1.2 8

Weed control b Grasses Broadleaf 6/22 6/13 3.25 9.0 4.75 5.5 8.5 9.5 7.0 9.5 6.5 4.5 2.25 1.75 7.0 9.7 10.0 5.7 6.5 10 10 10 10

Broadleaf 6/22 8.0 6.0 8.0 7.5 6.75 7.0 5.0 4.0 8.5 8.0 7.25 9.0

Lasso (alachlor) + Enide 90W (diphenamidc) Lasso (alachlor) + 10 7.5 5.75 Devrinol (napropamide) Furloe 124 7.7 9.5 9.5 (chlorpropham) Lasso (alachlor) + 2.0 7.7 9.7 9.5 Furloe 124 2.0 (chlorpropham) Prefar (bensulide) + 4.0 8.5 10 9.75 Furloe 124 2.0 (chlorpropham) Prefar (bensulide) + 4.0 9.0 1.5 2.0 Dual (metolachlor) 2.0 Devrinol (napropamide) + 0.5 9.0 7.0 7.5 Dual (metolachlor) 2.0 Dual (metolachlor) 2.0 8.2 7.2 7.0 Furloe 124 2.0 (chlorpropham) Untreated --9.7 0 .75 a Vigor scale ­ 0-10 with 0 = no vigor, 10 = excellent vigor b Weed control scale 0-10 with 0 = no control, 10 = perfect control c Out of production

10

8.0

9.7 8.0 9.5

8.5 8.5 5.5

5.5

5.75

Sesame appears to have good tolerance to diphenamid, bensulide, alachlor, and metolachlor and to a lesser extent chlorpropham. When used in combinations, good results are obtained in controlling grasses and broadleaves with some reasonable safety. Bensulide and chlorpropham combinations appear to have good potential. In Arizona, Howell et al. (1984) conducted two trials with PPI and PRE herbicides. The PPI were applied and incorporated the day of planting with a vibrashank 6-8 cm deep. The PRE were applied the day after planting. Both trials were pre-irrigated and then mulched with no rain until after emergence. In the second test there were very few weeds, and although ratings were taken, they were not considered conclusive because ratings were affected by which part of the field the replication hit. The varieties were Sesaco 2 and Sesaco 3.

Test 1 ­ S02 Test 2 ­ S03

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Appendix 1. Sesame herbicide research by country

Page 21

Treat PPI PPI PPI PPI PRE PPI PPI PRE PPI PRE PPI PRE PRE PRE PPI PPI PPI PPI PRE PRE PPI PRE PPI PPI PPI PRE PPI

a

Herbicide

Treflan (trifluralin) Treflan (trifluralin) + Caparol (prometryn) Treflan (trifluralin) + Caparol (prometryn) Prowl (pendimethalin) Dual (metolachlor) Dual (metolachlor) Lasso (alachlor) Lasso (alachlor) Dymid (diphenamid a) Dymid (diphenamid a) Dymid (diphenamid a) + Lasso (alachlor) Dymid (diphenamid a) + Lasso(alachlor) Dymid (diphenamid a) + Dual (metolachlor) Dymid (diphenamid a) + Dual (metolachlor) Caparol (prometryn) Caparol (prometryn) Prefar (bensulide) Prefar (bensulide) + Dual (metolachlor) Prefar (bensulide) + Lasso (alachlor) Check Check Out of production

Rate /ac 0.75 l 0.75 l 0.75 l 0.75 l 0.75 l 0.75 l 3l 3l 3l 3l 4.8 kg 4.8 kg 4.8 kg 3l 4.8 kg 3l 4.8 kg 3l 4.8 kg 3l 1l 1l 5l 5l 3l 5l 3l

Stand reduction 8 4 24 9 11 7 8 5 3 1.6 0.8 10 13 7 4 20 4 9 4 0 5

Stunt 33 15 63 35 50 23 34 23 23 17 13 30 48 33 18 53 19 48 20 14 10

Broadleaf control 58 89 90 54 89 94 84 98 90 91 99 96 99 98 84 88 55 90 91 0 0

Grass control 95 99 99 90 99 99 97 87 98 99 99 97 99 99 55 56 95 99 99 0 13

Stand reduction 1 2 50 2 2 3 0 0 0 0 0 0 3 1 6 46 0 3 0 0 0

Stunt 4 3 49 5 5 9 5 4 3 3 6 5 8 9 14 51 0 4 6 4 6

Using the criteria that 20% (adjusted to the control rating) or more stunt or 10% or more stand reduction or less than 80% weed control was unacceptable, they rated the treatments as follows for test 1 and 2:

Treat PPI PPI PPI PPI PRE PPI PPI PRE PPI PRE PPI PRE PRE PRE PPI PPI PPI Herbicide Treflan (trifluralin) Treflan (trifluralin) + Caparol (prometryn) Treflan (trifluralin) + Caparol (prometryn) Prowl (pendimethalin) Dual (metolachlor) Dual (metolachlor) Lasso (alachlor) Lasso (alachlor) Dymid (diphenamid a) Dymid (diphenamid a) Dymid (diphenamid a) + Lasso (alachlor) Dymid (diphenamid a) + Lasso(alachlor) Dymid (diphenamid a) Rate /ac 0.75 l 0.75 l 0.75 l 0.75 l 0.75 l 0.75 l 3l 3l 3l 3l 4.8 kg 4.8 kg 4.8 kg 3l 4.8 kg 3l 4.8 kg Mid stunt No/OK OK/OK no/no no/no no/no OK/OK OK/no OK/no no/no OK/no OK/no no/no no/OK Mid stand OK/OK OK/OK no/no OK/OK OK/OK OK/OK OK/OK OK/OK OK/OK OK/OK OK/OK OK/OK OK/OK Broadleaf control no/no OK/OK OK/OK no/no OK/OK OK/OK OK/OK OK/OK OK/OK OK/OK OK/OK OK/OK OK/OK Grass control OK/OK OK/OK OK/OK OK/OK OK/OK OK/OK OK/OK OK/OK OK/OK OK/OK OK/OK OK/OK OK/OK Early vigor OK/OK OK/OK no/no no/no no/no OK/OK OK/OK OK/OK OK/OK OK/OK OK/OK OK/OK OK/OK

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Appendix 1. Sesame herbicide research by country

Page 22

Treat

Herbicide

PPI + Dual (metolachlor) PRE Dymid (diphenamid a) PRE + Dual (metolachlor) PPI Caparol (prometryn) PRE Caparol (prometryn) PPI Prefar (bensulide) PPI Prefar (bensulide) + PPI Dual (metolachlor) PRE Prefar (bensulide) + PPI Lasso (alachlor) a Out of production

Rate /ac 3l 4.8 kg 3l 1l 1l 5l 5l 3l 5l 3l

Mid stunt no/no OK/OK no/no OK/OK no/no OK/OK

Mid stand OK/OK OK/OK no/no OK/OK OK/OK OK/OK

Broadleaf control OK/OK OK/OK OK/OK no OK/OK OK/OK

Grass control OK/OK no/no no/no OK/OK OK/OK OK/OK

Early vigor OK/OK OK/OK no/no OK/OK no/no OK/OK

Their conclusions were as follows: · Effective single controls were metolachlor (PRE), alachlor, and diphenamid. · Effective combinations were trifluralin/prometryn, diphenamid/alachlor, diphenamid/metolachlor, bensulide/metolachlor, bensulide/alachlor. · Overall diphenamid/metolachlor and diphenamid/alachlor were the most effective. · Application of PRE prometryn and PPI trifluralin/PRE prometryn resulted in stand reductions of 47 and 50% and stunting of 49 and 51%, respectively. · Although there was no ground cherry present in the trials, previous experience leads us to conclude that metolachlor, diphenamid/metolachlor, and bensulide/alachlor would provide good ground cherry control. · The following appear to be unacceptable: PPI trifluralin/PRE prometryn, pendimethalin, PPI metolachlor, PRE prometryn, PPI bensulide/PPI metolachlor. · PPI metolachlor and PRE prometryn were unacceptable, but PRE metolachlor and PPI prometryn were acceptable. In South Texas, Grichar et al. (2001a) conducted field studies from 1994 through 1997 in Yoakum and in Uvalde in 1995 to evaluate soil-applied herbicides for weed control, sesame tolerance, and yield. There were four replications. The varieties used were Sesaco 11, 17, or 18. The plant height was taken from averaging 5 plants and taken 5-7 weeks after planting. The data is as follows:

Herbicide Ethalfluralin Fluometuron Imazethapyr Metolachlor Rate kg/ha 0.6 1.3 0.3 1.1 0.04 0.07 0.6 1.1 2.2 3.4 1.1 0.6 1.1 0.4 1.1 0.4 Applic PPI PPI PRE PRE PRE PRE PRE PRE PRE PRE PRE/30D c PPI PPI PRE PRE PPI 1994 5 WAP a 35.6 21.6 b 11.6 b 7.1 b 38.7 46.5 38.1 38.7 40.4 Sesame height (cm) 1995 1996 7 WAP 6 WAP 43.7 b 49.5 28.2 b 46.5 120.0 47.5 127.5 51.3 117.9 40.4 120.9 38.9 123.7 50.8 125.7 53.6 119.1 48.0 124.0 50.5 122.2 51.5 73.1 b 55.6 b b 32.8 51.8 120.4 50.3 109.2 47.8 113.3 50.8 1997 5 WAP 67.4 43.2 b 77.5 73.2 75.7 70.6 70.9 78.0 70.1 76.7 75.7 67.8 53.3 b 44.7 b 13.7 b 74.4

Pendimethalin Prometryn Trifluralin

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Appendix 1. Sesame herbicide research by country

Page 23

Herbicide

Rate kg/ha 0.8

Applic PPI

Check LSD (0.05) a WAP = weeks after planting b Significantly different from check c D = days after planting

1994 5 WAP a 35.6 43.4 16.9

Sesame height (cm) 1995 1996 7 WAP 6 WAP 49.3 b 55.4 b 131.3 43.4 31.0 11.6

1997 5 WAP 70.3 70.9 14.7

Ethalfluralin significantly reduced plant height in most of the trials. Fluometuron had no effect on the height. Imazethapyr only reduced the height in 1994. Metolachlor had no effect on the height. Pendimethalin reduced the height in all the trials and significantly in 4 of the 8. Prometryn significantly decreased height in only one year. Trifluralin significantly reduced the height in one trial and yet significantly increased it in another. The sesame population was counted 4-6 weeks after planting. The data was as follows:

Plants/m of row Herbicide Ethalfluralin Fluometuron Imazethapyr Metolachlor Rate kg/ha 0.6 1.3 0.3 1.1 0.04 0.07 0.6 1.1 2.2 3.4 1.1 0.6 1.1 0.4 1.1 0.4 0.8 Applic PPI PPI PRE PRE PRE PRE PRE PRE PRE PRE PRE/30D PPI PPI PRE PRE PPI PPI 1995 2.8 a 3.0 a 66.5 70.8 54.5 63.0 62.8 84.0 91.8 60.0 61.8 6.0 a 8.5 a 24.0 a 8.5 a 14.0 a 1.5 a 70.3 23.5 1996 28.5 a 11.0 a 76.8 67.5 18.0 a 43.5 96.3 61.5 62.0 34.3 55.3 22.3 a 17.8 a 85.5 34.8 45.5 37.0 65.3 36.1 1997 14.7 a 0.6 a 67.5 75.0 47.4 a 62.4 50.1 48.6 a 58.5 59.1 67.8 10.2 a 1.8 a 14.4 a 1.5 a 22.8 a 14.1 a 67.5 18.8

Pendimethalin Prometryn Trifluralin

Check LSD (0.05) a Significantly different from check

Ethalfluralin lowered the population significantly in all trials. Fluometuron had no effect on populations. Imazethapyr lowered the population in all trials and significantly in two, but in the latter two it was not at the high rate. Overall, metolachlor increased and decreased populations but significantly decreased it in one trial. There was no pattern based on rate. Pendimethalin lowered the population significantly in all trials. Prometryn and trifluralin lowered the populations significantly except for 1996. The dinitroaniline herbicides were incorporated 2.5 cm deep which may have resulted in contact with the seed. The chemicals also may have moved down with moisture to be in contact. The weed control is based on 0 = not control and 100 = complete control. The weed control data was as follows:

Herbicide Ethalfluralin Rate kg/ha 0.6 1.3 Applic PPI PPI Broadleaf signalgrass 70 77 Brown-top panicum 100 100 Southern crabgrass 100 98 Palmer amaranth 1994 1995 58 79 98 100

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Appendix 1. Sesame herbicide research by country

Page 24

Herbicide Fluometuron Imazethapyr Metolachlor

Pendimethalin Prometryn Trifluralin Check LSD (0.05)

Rate kg/ha 0.3 1.1 0.04 0.07 0.6 1.1 2.2 3.4 1.1 0.6 1.1 0.4 1.1 0.4 0.8 -

Applic PRE PRE PRE PRE PRE PRE PRE PRE PRE/30D PPI PPI PRE PRE PPI PPI -

Broadleaf signalgrass 80 87 94 91 62 66 63 54 0 21

Brown-top panicum 84 99 94 90 95 96 98 99 96 99 100 65 90 100 100 0 10

Southern crabgrass 93 100 86 88 98 100 100 100 77 98 99 95 88 98 100 0 18

Palmer amaranth 1994 1995 95 100 92 85 62 49 37 47 0 25 98 100 95 99 95 99 100 100 100 100 100 97 100 99 97 0 4

Imazepyr and metolachlor provide the most consistent weed control (>80%). Ethalfluralin, pendimethalin, and trifluralin provide good grass control but were erratic on broadleaf control as would be expected. Fluometuron and prometryn were not tested in the worst year for weeds 1994, but did well in the other years. The weed control data was as follows:

Herbicide Ethalfluralin Fluometuron Imazethapyr Metolachlor Rate kg/ha 0.6 1.3 0.3 1.1 0.04 0.07 0.6 1.1 2.2 3.4 1.1 0.6 1.1 0.4 1.1 0.4 0.8 Applic PPI PPI PRE PRE PRE PRE PRE PRE PRE PRE PRE/30D PPI PPI PRE PRE PPI PPI 1994 Yoakum 470 360 460 340 a 1170 a 860 670 660 950 a 540 650 300 1995 Yoakum 720 740 810 630 790 720 760 990 740 650 1160 1470 a 870 310 1995 Uvalde 1600 a 1320 950 1170 1490 a 860 1210 1190 1170 1520 a 1440 a 1240 1620 a 110 a 70 a 1570 a 1500 a 870 470 1996 Yoakum 740 680 500 580 720 590 830 660 730 910 550 980 a 810 570 620 740 700 480 450 1997 Yoakum 700 a 710 a 440 400 470 480 450 470 380 420 470 600 580 540 400 670 a 660 a 480 180

Pendimethalin Prometryn Trifluralin

Check LSD (0.05) a Significantly different from check

The data in the following table was converted to a percentage yield compared to the check, but the average did not include 1996 where all of the herbicides exceeded the yields of the check.

Herbicide Ethalfluralin Rate kg/ha 0.6 1.3 Applic PPI PPI 1994 Yoakum 72 55 1995 Yoakum 1995 Uvalde 184 a 152 1996 Yoakum 154 142 1997 Yoakum 146 a 148 a Average 134 118

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Appendix 1. Sesame herbicide research by country

Page 25

Fluometuron

0.3 PRE 1.1 PRE Imazethapyr 0.04 PRE 71 0.07 PRE 52 a Metolachlor 0.6 PRE 1.1 PRE 2.2 PRE 180 a 3.4 PRE 132 1.1 PRE/30D Pendimethalin 0.6 PPI 103 1.1 PPI 102 Prometryn 0.4 PRE 1.1 PRE Trifluralin 0.4 PPI 146 a 0.8 PPI 83 a Significantly different from check

83 85 93 72 91 83 87 114 85

75 133 169 a

109 134 171 a 99 139 137 134 175 a 166 a 143 186 a 13 a 8a 180 a 172 a

104 121 150 123 173 138 152 190 115 204 a 169 119 129 154 146

92 83 98 100 94 98 79 88 98 125 121 113 83 140 a 138 a

95 101 108 81 108 106 120 127 116 124 136 67 75 159 134

By looking at the data in this way, it goes back to what Grichar said in the beginning that sesame with few weeds + some herbicide damage to the sesame is better than a lot of weeds + no damage to the sesame. The only herbicide that over all testing still averages below the check is prometryn although fluometuron and imazethapyr is a bit negative. Sesame has the ability to compensate for low stands by setting branches that load up with capsules. The overall conclusions were as follows: · Ethalfluralin at 1.26 kg/ha, imazethapyr at 0.04 and 0.07 kg/ha, and pendimethalin at 1.12 kg/ha reduced sesame plant height up to 66% when compared with the untreated check while pendimethalin, trifluralin, ethalfluralin, and imazethapyr reduced sesame plant stands 8-98% when compared with the untreated check. · Trifluralin, ethalfluralin at 0.63 kg/ha, and metolachlor at 3.36 kg/ha increased yield up to 80% over the untreated check. · Imazethapyr and metolachlor provided the most consistent weed control (>80%), while metolachlor provided the best weed control and least sesame injury. · The dinitroaniline herbicides [ethalfluralin, pendimethalin, and trifluralin] are options for weed control but crop safety is a concern if these herbicides are incorporated too deep in a shallow planted crop. In Texas, Grichar et al. (2001b) conducted POST OTT studies in weed free areas at Yoakum and Uvalde from 1994 to 1997. The varieties used were Sesaco 11, 17, or 18. The herbicides were applied over the top 3-4 wk after planting in Yoakum and 6 wk after planting in Uvalde. Sesame was 30-48 cm in height at the time of application. Planting dates in Yoakum were 26 May 1994, 11 July 1995, 12 July 1996, and 1 July 1997. Planting date in Uvalde was 28 April 1995. In 1995 none of the herbicides reduced stands while in 1997, stands were reduced as follows: acifluorfen low rate 65%, imazapic high rate 73%, and 2,4DB high rate 77%. Ratings of stunting (0= no stunting and 100 = total stunting) were done 3 weeks after herbicide application as shown below.

Rate (kg/ha) Check Acifluorfen Bentazon 0.28 0.56 0.56 1.12 94 YOA 0 83 89 38 65 95 UVA 0 78 65 55 33 95 YOA 0 30 43 9 14 96 YOA 0 70 83 7 23 97 YOA 0 79 91 5 20

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Appendix 1. Sesame herbicide research by country

Page 26

Bromoxynil Fluazifop-P Imazapic Imazethapyr Pyridate Sethoxydim 2,4-DB LSD (0.05)

Rate (kg/ha) 0.28 0.56 0.21 0.04 0.07 0.04 0.07 0.50 1.00 0.21 0.22 0.45

94 YOA 39 40 0 83 87 42 63 22 17 0 56 75 28

95 UVA 50 58 0 50 70 13 19 25 38 0 35 63 19

95 YOA 9 9 0 84 88 64 76 3 11 0 48 64 12

96 YOA 3 33 0 67 87 65 75 0 70 0 10 40 22

97 YOA 28 19 0 86 94 63 72 8 6 0 39 81 12

The grass herbicides (fluazifop-P and sethoxydim) did not show any stunting, but all of the broadleaf herbicides showed stunting. The effects on plant height (cm) were as follows:

Rate (kg/ha) Check Acifluorfen Bentazon Bromoxynil Fluazifop-P Imazapic Imazethapyr Pyridate Sethoxydim 2,4-DB LSD (0.05) Rate (kg/ha) Check Acifluorfen Bentazon Bromoxynil Fluazifop-P Imazapic Imazethapyr Pyridate 0.28 0.56 0.56 1.12 0.28 0.56 0.21 0.04 0.07 0.04 0.07 0.50 0.28 0.56 0.56 1.12 0.28 0.56 0.21 0.04 0.07 0.04 0.07 0.50 1.00 0.21 0.22 0.45 94 YOA 91 7 0 76 45 71 49 103 0 0 61 34 77 83 105 34 8 26 94 YOA 408 0 0 286 86 0 0 658 0 0 267 282 210 95 YOA 110 69 80 110 103 107 99 84 35 68 78 49 111 109 126 65 75 32 95 UVA 844 650 820 692 786 793 822 783 260 107 413 390 432 96 YOA 71 41 12 58 45 54 48 53 27 23 30 18 62 34 68 61 42 23 95 YOA 482 109 146 432 460 427 309 754 363 344 608 484 325 97 YOA 74 34 35 67 63 53 57 65 25 17 45 36 50 64 75 53 34 16 96 YOA 419 159 174 237 195 307 255 273 46 81 897 18 0 97 YOA 501 665 548 528 549 514 427 604 582 564 548 470 531 Avg 531 317 338 435 415 408 363 614 250 219 547 329 375 % check 60 64 82 78 77 68 116 47 41 103 62 71

The yields (kg/ha) were as follows:

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Appendix 1. Sesame herbicide research by country

Page 27

Sethoxydim 2,4-DB LSD (0.05)

Rate (kg/ha) 1.00 0.21 0.22 0.45

94 YOA 345 704 15 61 248

95 UVA 836 849 578 454 210

95 YOA 487 754 260 280 255

96 YOA 282 381 264 192 217

97 YOA 504 621 407 374 NS

Avg 491 662 305 272

% check 92 125 57 51

The fluazifop-P and sethoxydim were the only herbicides that did not reduce the yield and actually increased the yield by controlling the grasses. The 2,4-DB, acifluorfen, imazapic, and high rate of imazethapyr were the most harmful. The low rate of imazethapyr helped the yields primarily by controlling weeds. Although bromoxynil and bentazon reduced the yields by 25%, they are the choice for an over the top POST if the broadleaf weeds are so bad that the field can be lost. In Texas, Grichar and Langham (2003) conducted a POST test in Batesville. A 5 ft swath of herbicides was sprayed across three rows of five lines leaving 15 ft of each row untouched to allow a direct within row comparison of the effects of the treatments. The herbicides were sprayed over the top in the juvenile stage when the plants were about 18" tall. There was a dual purpose: (1) find herbicides that were selective to sesame and (2) find herbicides that would control volunteer sesame in other crops. In this test, there were no weeds since the main thrust of the study was to look at the effects of the herbicide on the sesame. There were no replications in that the idea was to take the better lines and test them in Grichar et al. (2007). At the end of the ripening phase, the plots were evaluated in terms of percentage production compared to the untouched line in the same row.

Treatment Lactofen Prometryn Atrazine Glyphosate Prosulfuron Mesotrione Nicosulfuron Imazethapyr Dicamba Diflufenzopyr Rimsulfuron Diclosulam Rate 0.5x 1.0x 0.5x 1.0x 0.5x 1.0x 0.5x 1.0x 0.5x 1.0x 0.5x 1.0x 0.5x 1.0x 0.5x 1.0x 0.5x 1.0x 0.5x 1.0x 0.5x 1.0x 0.5x 1.0x S26 50 40 60 40 60 40 5 5 40 30 40 30 30 20 40 40 10 20 10 10 50 30 30 30 S27 60 50 60 50 60 50 10 10 50 60 40 50 60 20 70 50 10 20 50 30 70 40 60 50 S28 50 50 60 40 60 40 20 5 50 50 40 30 40 20 40 40 30 10 10 10 60 40 30 30 S29 50 50 60 40 60 60 20 5 80 50 60 60 60 40 50 50 40 50 40 40 50 40 50 40 132 40 30 70 40 50 40 5 5 40 30 30 40 60 10 30 20 20 10 20 10 50 20 20 10 Average 50 44 62 42 58 46 12 6 52 44 42 42 50 22 46 40 22 22 26 20 56 34 38 32

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Appendix 1. Sesame herbicide research by country

Page 28

Treatment GCA Acifluorfen Imazapic 2,4D-B Bromoxynil Chlorimuron Prosulfuron Oxyfluorfen Fomesafen Clethodim

Rate 0.5x 1.0x 0.5x 1.0x 0.5x 1.0x 0.5x 1.0x 0.5x 1.0x 0.5x 1.0x 0.5x 1.0x 0.5x 1.0x 0.5x 1.0x 0.5x 1.0x Average

S26 10 20 60 50 60 70 30 30 40 40 50 50 40 30 40 30 30 40 100 100 37

S27 30 60 70 40 60 70 50 50 50 50 70 80 60 60 40 30 40 70 100 100 49

S28 20 40 60 50 60 50 30 20 50 40 50 50 30 30 30 20 30 50 100 100 37

S29 30 60 60 60 80 50 40 80 50 40 60 60 40 30 30 30 40 50 100 100 48

132 20 30 50 40 40 50 20 20 49 30 50 30 30 20 30 30 40 40 100 100 31

Average 22 42 60 48 60 58 34 40 48 40 56 54 40 34 34 28 36 50 100 100 40

With an average production of 40% most treatments were in the middle in terms of production. The following generalizations were made: · S27 and S29 did better against the herbicides than the other lines. · In most of the lines there was less production in the high treatment, but there are a few exceptions. · Only one herbicide had no effect on sesame: clethodim. All others have to be considered toxic to sesame with substantial reduction in production. · Only one herbicide controlled sesame: glysophate. The plants that were not affected were minor plants that were shielded under the canopy by the dominant plants. In Texas, Grichar and Dotray (2007) conducted PRE and POST OTT studies in two locations (Yoakum and Lubbock) in 2004 and 2005. The data from the PRE tests was as follows:

Treat Check Cloransulam S-metolachlor Diclosulam Prometryn Fluometuron Diuron Flumioxazin Rate kg/ha 0.04 1.42 0.03 1.12 1.12 1.12 0.07 0.11 0.14 1.12 0.07 Weed control AMATU BRAPP 0 0 90 30 99 91 99 61 89 52 100 61 99 93 100 48 100 67 100 91 99 36

a, c

Norflurazon Pyrithiobac

Stand reduction b 2004 2005 Lub Yoa Yoa 0 0 0 100 94 82 0 9 0 100 86 96 43 58 27 9 13 0 30 13 5 94 100 100 100 100 100 94 100 100 58 30 48 77

Injury b 2004 2005 Lub Yoa 0 0 100 18 0 0 100 26 53 14 0 0 17 3 77 100 100 100 88 100 28 75 8

Yield c 2005 kg/ha 380 104 546 64 418 402 208 0 0 0 186

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Treat Flufenacet + metribuzim S-metolachlor + metribuzim Rimsulfuron Flufenacet

94 67 5 23 1 297 92 69 6 97 0 57 94 78 72 100 14 54 LSD (0.10) 15 28 40 25 29 29 18 217 a Bayer code for weeds: AMATU (Amaranthus tuberculatus) tall waterhemp, BRAPP (Brachiaria platyphylla) broadleaf signalgrass b Stand reduction and injury index: 0 = no stand reduction or sesame injury; 100 = complete stand reduction or plant death c Weed control and sesame yield taken at the Yoakum location only

Rate kg/ha 0.14 0.21 1.50 0.35 0.03 0.84 1.68

Weed control AMATU BRAPP 89 66 90 56

a, c

Stand reduction b 2004 2005 Lub Yoa Yoa 74 49 49 100

Injury b 2004 2005 Lub Yoa 25 4

Yield c 2005 kg/ha 305 88

The conclusions were as follows: · Although broadleaf weed control was excellent with all PRE herbicides evaluated, the potential for severe sesame injury limits the use of many soil-applied herbicides for broadleaf weed control. · Metolachlor has provided excellent sesame tolerance in previous studies. · Of the other soil-applied herbicides evaluated, fluometuron, diuron, and rimsulfuron show the most potential for possible use in sesame production. · In a previous study (Grichar et al. 2001a) reported that metolachlor and fluometuron showed the greatest potential for possible use in sesame. The POST OTT experiments were as follows. The herbicides were applied in the prereproductive stage when the plants were about 60 cm tall. The data from the POST OTT tests was as follows:

Sesame injury (%) a Yield (kg/ha) Rate 2004 2005 2004 2005 Treatment b kg/ha Lub Yoa Lub Yoa Lub Lub Yoa Check 0 0 0 0 125 1,008 314 Lactofen 0.20 99 57 38 25 0 698 320 Prometryn 1.12 48 30 16 7 27 835 476 Acifluorfen 0.56 82 38 33 18 8 641 657 Bromoxynil 0.56 37 40 25 10 39 883 638 Fomesafen 0.21 55 53 15 13 28 896 621 Rimsulfuron 0.03 99 78 63 28 0 347 485 Cloransulam 0.02 58 72 25 45 23 799 284 Diclosulam 0.02 96 85 73 42 4 414 312 Pyrithiobac 0.04 100 67 142 S-metolachlor 1.12 10 8 105 1,060 LSD (0.10) 11 36 20 105 226 a Injury index: 0 = no sesame injury; 100 = complete plant death. Ratings taken 6-8 wks after herbicide application b All herbicides included a non-ionic surfactant added at 0.25% v/v or a crop oil concentrate added at 1 qt/ac.

Their conclusions were as follows: · In Lubbock where there were no weeds, all treatments except S-metolachlor reduced the yields from mildly to severely, while in Yoakum with weeds, the treatments by controlling the weeds had higher yields than the control. · S-metolachlor caused the least amount of sesame injury followed by prometryn and fomesafen.

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·

Bromoxynil showed similar results as in a previous study, where Grichar et al. (2001b) reported that bromoxynil was intermediate in sesame injury.

Grichar, Dotray, and Langham experimented with POST DIR treatments in Uvalde and Lubbock in 2006. The experiment is being repeated in 2007. The variety used was Sesaco 29 planted 25 May in Uvalde and 20 June in Lubbock. The herbicides were applied 2" and 6" from the ground on both sides of the stem when the plants were about 18" tall in the juvenile stage. The treatments were replicated 3 times. In Uvalde the experiment was under a lateral pivot with extreme variation. As a result the yield data was taken by cutting a sample within the treatment and a sample in the adjacent untreated row. The yield below is a percent of the treated row divided by the untreated row. The Lubbock experiment was rainfed with some variation between rows, and the percentage yield below represents the treatment plot divided by the check plot. In both locations the day after planting, a PRE treatment of metolachlor plus glyphosate was sprayed over the fields. There was no weed pressure in either location since the purpose of the initial experiment was to find herbicides that would be selective to sesame.

Active ingredient Carfentrazone Prometryn + Glyphosate Lactofen Diuron + Glyphosate Trifloxysulfuron Pyraflufen-ethyl Paraquat Glufosinate Linuron and diuron Glyphosate Pyrithiobac Prometryn Flumioxazin + Glyphosate Rate lbs/ ac 0.016 1.0 0.75 0.2 0.75 0.75 0.007 0.016 0.25 0.52 1.0 0.75 0.063 1.0 0.063 0.75 Height of applic 2" 6" 2" 6" 2" 6" 2" 6" 2" 6" 2" 6" 2" 6" 2" 6" 2" 6" 2" 6" 2" 6" 2" 6" 2" 6" Stunting Lub 0 5 0 3 0 5 0 5 0 3 0 5 0 0 3 6 0 0 13 30 17 43 0 5 0 5 Uva Yield % of check Lub Uva 99 91 88 88 75 110 65 85 81 87 74 79 62 90 46 84 96 123 86 81 96 78 95 88 103 98 84 88 91 108 88 108 100 126 89 88 86 130 44 116 67 76 64 55 85 112 94 114 56 108 64 108

· In most cases the higher the herbicide was sprayed, the lower the yield. Most commercial hooded sprayers can spray at the 2" level, but in uneven fields will spray about 4". · In Uvalde the only herbicide that severely damaged the sesame was pyrithiobac. · In Uvalde many of the treatments with glyphosate actually improved the yield. In close examination, there was a high population and the glyphosate killed the minor plants under the

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canopy and thus thinned the population. In a very high population the minor plants are in effect a weed because they use moisture and fertility without giving commensurate yield. · In Lubbock, the glyphosate treatments reduced the yields ­ at times substantially. · There is no one product that looks best, but there are several promising: Layby Pro which is a combination of linuron and diuron looked the best. Glufosinate, paraquat, and prometryn also show some potential. · The ideal is to have a product that will have burndown on existing weeds and some residual control over future flushes of weeds. In South Carolina, Brad Sadler (2007, pers. commun.) has grown sesame for bird hunting for the past 20 years. He has used both Lasso (alachlor) and Dual (metolachlor) in alternating years in order to control yellow and purple nut sedge. He waits for a good probability of rain and then sprays the material and incorporates it before planting. He has had good stands with both materials. He has not noted any difference on the sesame with either product. In a few years he has sprayed Lasso and Dual over the top of the seedlings and found no damage with the alachlor and some set back from the metolachlor. However, both ended up with normal crops. In South Texas, Grichar conducted PRE, SYS, POST OTT, POST DIR, and harvest aid tests in Uvalde in 2007.

On the Caprock of Texas, Dotray conducted PRE, SYS, POST OTT, POST DIR, and harvest aid tests in Lorenzo in 2007. In Oklahoma, Godsey conducted PRE tests in Stillwater in 2007. VENEZUELA Mazzani (1957) tried several PRE herbicides: Premerge (dinoseb [OP]) and 2,4D reduced the germination too much. Cloro IPC (chlorpropham), Karmex (diuron), TCA (sodium trichloroacetate), and pentachlorophenol (all at rates between 0.6 and 1.2 kg/ha) controlled the weeds, but the most promising results were with diuron at 0.6 to 1.2 kg/ha. Different combinations of PRE rates of Karmex were tried over the seed line and between the seed lines with the following results:

Treatment (kg/ha) Above seed line Between seed lines 0.6 1.2 0.8 1.6 0 1.6 Control with weeding Number of plants 12 days 20 days 41.8 (111.7%) 30.8 (83.3%) 41.4 (110.7%) 33.8 (90.4%) 41.6 (111.2%) 41.6 (111.2%) 37.4 (100%) 36.0 (96.2%) Yield kg/ha 700.8 626.8 501.4 1,071.2

Although the diuron did not have much of an effect on the plant stands, and the seedlings appeared to recover, all treatments reduced yields. However, with the amount of weeds in the test area, the yields would have been much lower if there had been no weed control. Montilla (1964) had three experiments with Dymid (diphenamid [OP]), Karmex (diuron), Lorox (linuron), Amiben (chloramben [OP]), and Treflan (trifluralin). · In the first experiment, the herbicides were applied PRE.

Treatment Diuron Dose/ha 1l 1.5 l Broad cont 85 86 Grass cont 64 81 Sesame germ Good Good

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Treatment Diphenamid

Chloramben

Linuron

Dose/ha 2l 2 kg 4 kg 6 kg 9 kg 2l 4l 8l 1 kg

Broad cont 93 14 21 40 16 20 22 12 67

Grass cont 82 58 68 70 92 49 61 77 40

Sesame germ Regular Good Good Good Good Good Regular Regular Good

The best products were diuron and diphenamid; however in some of the replications of diphenamid there was toxicity and the sesame plants did not develop well. · In the second experiment, the herbicides were applied pre-plant incorporated. They tried trifluralin (1, 2, 3 l/ha) and trifluralin/diphenamid (4+1, 4+2, and 6+1 l/ha). The sesame did not germinate in any of the treatments. · In the third experiment, he compared Venezuela 52 and Aceitera using diuron and diphenamid with the following results.

Treatment V 5 2 Diuron Diphenamid Check Treatment A c e Diuron Diphenamid Check Dose/ha 1l 4 kg 6 kg Broad cont % 94 87 93 Grass cont % 94 87 93 Dose/ha 1l 4 kg 6 kg Broad cont % 64 83 83 Grass cont % 96 86 90 Plant height cm 100 133 110 114 Plant height cm 96 100 101 105 Yield kg/ha 550 784 633 450 Yield kg/ha 784 867 718 583

Although neither had complete control of the weeds, they controlled enough to improve the yield over the check with no control. Weiss (1971) cited Mazzani (1966) that monuron [OP] (1 kg/ha) and diuron (1.5 kg/ha) applied PRE gave reasonable control of weeds with no effect on the crop.

Mazzani (1999) cites the following data from Caraballo et al. (1986). In experimental plots the best results were from using Lazo (alachlor at 3-4 liters/ha) as a PRE and Karmex (diuron at 2 liters/ha) as a POST OTT. Lazo dose, l / ha Plant height, cm Yield, kg / ha 6 174 1,008 5 170 833 4 172 848 3 170 810 Cleaned by hand 166 1,042 No cleaning 154 536 They also compared the different times of spraying using diuron 80 (1,5 liters/ha plus 0.5 liters of surfactant): Number of days after planting Plant height, cm Yield, kg / ha 15 159 947 22 158 896 29 153 817

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Number of days after planting 36 43 50 Cleaned by hand No cleaning

Plant height, cm 158 149 154 160 144

Yield, kg / ha 911 762 770 1,117 557

This product controlled 94% of the broadleaves and 89% of the grasses. The sesame plants suffered a bit of discoloration on the lower leaves when the product was sprayed directly into the row but returned to green in a short time.

Mazzani (1999) cites Villaroel et al. (1988) also showed the most efficient control with Lazo (alachlor) at a dose of 3.5 liters/ha.

Pineda and Avila (1988) tried alachlor (Lazo) and pendimethalin (Prowl) at 4 and 2 l/ha respectively applied at planting. They tried this is combination with some fungicides to control Fusarium and Macrophomina. The alachlor was comparable to the check, but there were problems with the pendimethalin on germination and growth of the plants. In a grower guide, Avila (1999) states that PRE herbicides are no longer used because there is a lot of rain around planting time making the herbicides erratic, inefficient, and costly. When the plants are about 30 cm tall, Karmex (diuron) is used at 1.5 l/ha with 2 liters of surfactant. The diuron controls the weeds and does not damage the sesame. For grasses, fluazifop at 200 to 400 cc/ha works well FIRST AUTHOR EXPERIENCE Over the past 65 years, weed control in sesame has been a major concern of D.G. and D.R. Langham. In Venezuela, D.G. Langham bred for varieties that had large leaves and would grow as quickly as possible to close the canopy. In breeding branching varieties, he found that they could be planted on wider spacing, but the unbranched varieties needed closer spacing in order to close sooner (D.G. Langham and Rodriguez 1945). Most of the materials grown from Southern Mexico to Paraguay come from the original Venezuelan varieties ­ most have the phenotype of Venezuela 52 with large leaves and aggressive growth. However, in moving to combining sesame direct, these tall, leafy plants are a problem for the reel in front of the combine and the augers in the header feeding the combine. In reducing the size of the plant and the leaves to resolve these mechanical problems, there is a later canopy and more light into the ground, making the use of herbicides even more important. In the research nurseries planted by the Langhams in Venezuela, Connecticut, California, India, and Arizona, no herbicides were used. In all but Arizona, weed control was done primarily by manual labor. In Arizona, the practice was to pre-irrigate on laser leveled fields, do a mulching operation, and then plant. The mulching operation destroyed the weed seedlings with rare rains between sesame emergence and canopy formation. In moving the research to Texas and Oklahoma, weeds became a major problem in the nurseries. From 1988 through 1997, trifluralin (Treflan) PPI was applied, and from 1998 to the present, PRE S-metolachlor (Dual magnum) and glyphosate (Roundup) has been used. In addition to the nursery work, the first author has cooperated on herbicide experiments with Howell (1984) in Tacna, Arizona, Grichar (2001a, 2001b, 2007) in Yoakum and Uvalde, Texas, with Dotray (2007) in Lubbock, Texas, and with Lanfranconi (2007) in Salta, Argentina. The author has also observed tens of thousands of commercial sesame hectares in Mexico, Guatemala,

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Venezuela, Paraguay, Argentina, the Republic of Korea, Thailand, India, and Turkey, and has exchanged data with researchers in many other countries. Within the US the observations have been on nurseries, herbicide trials, planting seed fields, fields with drift from herbicides in adjacent crops, tens of thousands of hectares of sesame planted after hailed out crops that had their herbicides in place, tens of thousands of hectares that have followed winter crops such as wheat with their herbicide residues, and tens of thousands of hectares that have followed summer and fall crops with their herbicide residues. The following summarizes the observations of the first author outside of the herbicide trials that are documented in other portions of the paper. The trade names in parenthesis are the ones observed. 2,4D-B (Butyrac) · When 2,4D-B is used along the edges of the field for border weed control, there is injury to the sesame but usually it is not killed. · In a nursery in Oklahoma, 2,4D-B was sprayed on peanuts to the south on a non-windy day. Although the sprayer stayed over 20 m away from the sesame field, there was drift that damaged the sesame close to the peanuts, and there was evidence of drift as much as 100 m into the nursery. The affected plants had twisted stems and did not produce capsules for up to a week. There was more effect on some lines than on others. · When a farmer used 2,4D-B in a mix with glyphosate as a burndown PRE, the germination was reduced substantially. Acifluorfen (Blazer) · In the Lubbock nursery in 2005, the farmer was using acifluorfen on cotton and POST DIR sprayed a sesame strip (the juvenile stage while 20" tall) filled with morningglory with the chemicals hitting the stems of the sesame about 3" from the ground. There was no visible damage to the sesame. Most of the existing morningglory plants were killed, but there was another flush with the next rain. · In Batesville, a planting seed farmer did not get metolachlor sprayed PRE over an 8 row strip in the field and there were considerable weeds in that area. A POST DIR spray of acifluorfen at 4" did not damage the majority of the sesame, but did kill minor plants where the percentage of the stem sprayed was higher because the plants were shorter. The weeds were as high as the sesame, and the herbicide did not kill all of the weeds but set back most of them so that few weeds were not visible above the sesame at the end of the season. There was a mark that resembled a bruise on the sesame stems where the spray hit. Atrazine (Aatrex) · Tens of thousands of acres of sesame have been planted after corn and sorghum the summer before, and there is only one known problem. In one year, there was very little rain between the fall application of atrazine and the planting of the sesame in the spring. The sesame stand was lost, and extension personnel felt that the plants had herbicide damage. · There has been no attempt to plant sesame after hailed out corn or sorghum for fear of atrazine damage. Bromoxynil (Weedex) · In Argentina, there was a sesame field that was clean from the metolachlor PRE, but at about 34 weeks there was a severe flush of nabo (Raphanus sativus). Bromoxynil was applied over the top and it did not kill the nabo or the sesame, but it set the sesame back severely to the point that the nabo grew over the sesame and reduced yields substantially. In the one area where the

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bromoxynil was applied earlier when the nabo was young, there was reasonable weed control and the sesame was taller. Clethodim (Select) · Clethodim has a faster and more lasting kill of johnsongrass than the other grass herbicides. · In 2003, clethodim was applied by a ground rig on one field at the mid bloom stage, and the plants were shut down on flowering for almost two weeks. The plants then again began to put on flowers and capsules, but never fully recovered compared to the plants near some of the edges that never were sprayed. Similar results were seen in the pre-reproductive stage when applied by a ground rig, but the plants recovered better and the damage could not be seen at the end of the crop. In previous experiments Grichar had never seen any effect on the sesame, and thus it was hypothesized that the crop oil did the damage instead of the clethodim. Grichar and Langham then applied every permutation from 0 to 3 times recommended rate of the crop oil and clethodim to a nursery in the mid bloom stage, and no effects were seen. It was concluded that the two problems had been flukes. · In 2004, clethodim was applied to a field by air in the mid bloom stage and the same results were seen, but not as severe as in 2003. Another application by a ground rig in the prereproductive stage again set back the sesame, but the damage could not be seen at the end. · In 2005, Grichar and Langham theorized that the triple application experiment might have been applied in a later stage and thus repeated the experiment of tripling the recommended rate at the same stage as the 2003 and 2004 fields and again no effects were seen in 2005. In observing sesame next to Roundup Ready cotton, the same symptoms were seen on the sesame near the cotton where there had been drift. By this point it was theorized that perhaps there were glyphosate residues in the tanks of the farmers and commercial applicators. · In 2006, there were experiments in the early bloom stage by Grichar, Dotray, and Langham in Uvalde and Lubbock using traces of glyphosate mixed into the glyphosate while again testing the clethodim up to the 3x rate. No damage was seen in the pure clethodim treatments, but the crop damage that had been seen in 2003 and 2004 was repeated in the replications with glyphosate as a trace. The conclusion was that as more farmers use glyphosate as their primary method of weed control, there is a build-up of glyphosate in the tanks. In talking to farmers, many leave glyphosate in their tanks between applications and do perfunctory cleaning prior to other chemicals. It is theorized that these residues then dissolve in the clethodim causing the damage. · An application during flowering using a quarter rate of clethodim and three quarters of fluazifop-P had excellent johnsongrass kill and no damage to the sesame. · Appling clethodim when sesame is not flowering has not had any problems. Diuron (Direx) · Cotton farmers apply diuron PRE and POST. On hailed out cotton, there has never been a problem with sesame stands on fields that had used diuron. · In the Lubbock nursery in 2005, the farmer was using diuron on cotton and POST DIR sprayed a strip of sesame (the juvenile stage while 20" tall) with morningglory with the chemicals hitting the stems of the sesame about 3" from the ground. There was no visible damage to the sesame. The existing morningglory plants were killed, but there was another flush with the next rain. Fluazifop-P (Fusilade) · Fluazifop-P has been applied in many stages and in many ways without any damage to the sesame. It has been applied as early as the seedling stage (first true leaf) through late drydown stage. It has been applied by back-pack, ground rig, and from the air.

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· The only problem with fluazifop-P has been that it is not always effective against the johnsongrass if it gets too tall and is no longer growing. Although it is easy to kill johnsongrass from seeds, it is difficult to kill the rhizomes and that johnsongrass may emerge later in the season. Flumioxazin (Valor) · In the Lubbock nursery in 2005, the farmer was using flumioxazin on cotton and POST DIR sprayed a sesame strip (the juvenile stage while 20" tall) with morningglory with the chemicals hitting the stems of the sesame about 3" from the ground. There was no visible damage to the sesame. The existing morningglory plants were killed, and there was excellent control the rest of the season. Glyphosate (Roundup, Buccaneer, Durango) · Glyphosate has been used PREPLANT extensively to kill off the weeds. Within the nurseries, glyphosate has been added PRE along with the metolachlor after planting to kill weeds that have not been killed by the harrowing. There has never been a stand of sesame lost because of glyphosate. However, there are soils that crack and in high temperatures sesame germinates quickly. Glyphosate should not be applied more than 2 days after planting even if sesame is not above the ground because there is a chance that the seedling is exposed from cracks in the seed bed. · In one known case where the glyphosate was applied 3 days after planting, there was little emergence in the area planted first and then there was less population and by mid field, there was a good stand. · When glyphosate is used along the edges of the field for border weed control, there is injury to the sesame but usually it is not killed. · In one case where glyphosate was flown on to an adjacent field, there was drift which killed the sesame near the other field and then a gradual severe to moderate to no injury into about 30 meters of the sesame field. · After planting sesame, with the use of Roundup Ready cotton, there are no problems with sesame as a weed in cotton as there was in previous years. · Within sesame, farmers have successful used glyphosate with a wick and controlled the weeds without damage to the sesame. The one exception was when there was a leak in the wick and there was a row of severely stunted sesame the same distance from the tires of the tractor throughout one field. · Hooded sprayers with the side nozzles turned off have controlled weeds in the furrow without damaging the sesame. · In the Lubbock nursery in 2005, the farmer was using glyphosate on cotton and POST DIR sprayed a sesame strip (the juvenile stage while 20" tall) with morningglory with the chemicals hitting the stems of the sesame about 3" from the ground. There was no visible damage to the sesame. The existing morningglory plants were killed, but there was a flush of new morningglory later. However, the rate is critical since when the tractor stopped and did not turn off the spray immediately, all of the plants in 8 rows for 4 ft died. Imazapic (Cadre) · Sesame has followed peanuts that had imazapic with good stands. In one year there was a nursery planted next to peanuts and six rows had virtually no stand. In talking to the person that had applied the imazapic to the peanuts he admitted that part of the boom went over 6 rows of intended sesame nursery. There were a few lines of sesame that had perfect stands in the 10 meters they were planted, but this apparent tolerance has not been followed up because of the

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long plant-back restrictions. Sesame is primarily a rotation crop, and the fields need to be rotated back to the primary crop. · Thinking that because there was some resistance in some lines from a PREPLANT application of imazapic, imazapic was applied POST OTT over 27 lines that included the resistant lines plus lines that were progeny from the resistant lines. Imazapic was toxic to all the lines, but did not kill any of the sesame. Linuron (Lorox) · Linuron has been applied POST DIR in multiple passes when the sesame is in the early reproductive through mid bloom stages while it is still possible to get ground rigs into the fields. The linuron has controlled morningglory. The leaves at the bottom of the sesame were affected, but the plants did not die and there was no effect on the upper canopy. There was no side by side comparison with a control to see the effects on yields, but visually the crop terminated normally. Metolachlor (Dual Magnum, Medal) · From 1998 through the present the practice in the Sesaco nurseries has been to pre-irrigate, harrow, plant the nurseries and experimental fields, and apply metolachlor and glyphosate within 2 days of planting. The glyphosate kills weeds that escaped the harrowing operation. In most years there is no rain until the sesame is up, but on two occasions, rain has activated the metolachlor and carried it into the soil, and the sesame plants came through it. There has never been a detectable difference in stand or injury, but a check without metolachlor has not been planted within the nurseries. · In some fields there is a difference in moisture across the field and while most of the seed is planted into moisture, some ends up in dry dirt. Applying a pivot across the field to activate the metolachlor, has brought up sesame to fill in the stands. It is assumed that the water imbibed by the seed had herbicide and that the layer of soil between the seed and the surface had herbicide. There was no digging of seedlings to determine if there were seedlings that had been damaged by the herbicide that did not emerge. · In one year, it rained about 10 mm before the metolachlor/glyphosate had been applied preventing the ground rig from entering the field. The metolachlor was chemigated on with a pivot about the time that the seedlings were emerging from the ground. The sesame that had been in dry soil germinated and emerged to form a good stand. There was no digging of seedlings to determine if they had been damaged by the herbicide and did not emerge. There was no damage to the seedlings that emerged. · In Argentina, metolachlor was applied on one field after planting and on three others before planting. All four fields had rains after planting and before seedling emergence. The stands on all of the fields which totaled 240 ha were excellent. The weed control initially was excellent, but with continual rains there were problems in two of the fields. In the first field, there was a rain between the PREPLANT application and three rains between planting and emergence. On this field, one field half was planted with metolachlor and the other half with trifluralin. The stands were similar, but there were less weeds in the half of the field with the metolachlor. In the other field, there was a flush of nabo (Raphanus sativus) about 3 weeks after planting. In this field, a full nabo crop was allowed to go to seed after the previous wheat crop. Any herbicide with 99% control of a weed will do reasonably well in the presence on millions of weed seeds, but will not look as effective in a field with hundreds of millions of weed seeds. · One of the concerns of metolachlor is that it takes rainfall (or irrigation) to activate it. The people that use it have the following philosophy: if there is a rain, it will be activated and will provide weed control, and if it does not rain, there is no need for weed control. The metolachlor does not provide control against later flushes of weeds, but by that time, the crop

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Appendix 1. Sesame herbicide research by country

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canopy has closed in and there are fewer problems with weeds. The exception is with weeds such as morningglory that come through weak light and climb the plants to reach the light. Pendimethalin (Prowl) · In Texas there are farmers that swear by trifluralin and neighbors that swear by pendimethalin. In planting nurseries with pendimethalin, it was used similarly to trifluralin in terms of dose and farming practices. The author has less experience with pendimethalin, but it was used when planting nurseries with farmers that use pendimethalin. · In the first year of planting, a full cotton rate of trifluralin was used, and there was enough of a stand reduction that a half rate was tried successfully. From that point forward, the pendimethalin rate was also cut in half. · The practice in the nurseries was to pre-irrigate, apply the pendimethalin at half cotton rate, incorporate it with a harrow, and plant. The pendimethalin did a good job controlling grasses and pigweed. · In some years in pulling up plants, there was some root pruning, but the plants still matured and looked normal. There was never an attempt to see if the pendimethalin had lowered the yield. In the yield sampling in the breeding program, the averages changed from year to year, but the changes could always be correlated to irrigations, fertility, and weather. There was never any reason to suspect that the pendimethalin affected the yield in a negative way, but it did affect the yield in a positive way by controlling weeds. · Starting back in 1987 there has been sesame planted after hailed out cotton. Pendimethalin had been applied prior to planting with different practices ­ some apply it in February/March and others apply it closer to the planting of cotton that ranges from late April to early June. With US insurance policies if there is a hail out prior to a certain date (the date varies with the area), then cotton has to be replanted, but after that any crop can be planted. Most of the sesame after hailed out cotton has occurred in the mid June to early July time-frame. There has never been a loss of a sesame stand after failed out cotton due to pendimethalin. It is not known if there is no effect because the pendimethalin has been diluted through rains into different ranges of soil or if the pendimethalin loses its potency over time. · In using pendimethalin it is critical to place the seed in the moisture below the hot zone of the pendimethalin. Dry soil with pendimethalin has been pulled over the seed line without an effect. There have been problems when there is a rain after the pendimethalin has been applied/incorporated and before the planting. In these cases, the seed is placed in the hot zone, and the stand can be damaged or even lost. · In cold weather, the sesame plants take longer to germinate and grow even more slowly. Pendimethalin appears to damage the plants more when it is colder than when it is warmer and the sesame germinates and grows faster. · As with trifluralin, in most cases pendimethalin works, but there have been fields that were completely lost because the pendimethalin reduced the stands substantially. · As more and more farmers move to no-till practices, pendimethalin will not be as good an option since it has to be incorporated or it will lose its effectiveness. With products such as Prowl H2O, the problem may be solver; however, there are mixed results to date among farmers. Prometryn (Caparol) · In Arizona the prometryn initially looked very promising for use in sesame. However, in one year there was zero stand of sesame on fields with prometryn. In analyzing the differences, in the initial years the double disc opener planters had packing wheels that closed the seed line. In some fields, the closers left a gap and the seed line dried out. Chains were attached to the back of the planter boxes to pull dry dirt over the seed line and cover the gap, and suddenly there was

Use only herbicides approved and tested in your area

Appendix 1. Sesame herbicide research by country

Page 39

no stand with prometryn. Essentially, in the early years the planter was peeling back the hot zone of prometryn over the seed line and not bringing it back over the line. With the chains, the hot zone was brought back over the top. Lifting of chains on every other planter box on the tool bar confirmed the theory in that the rows without the chains had perfect stands except where the soil dried out, and there was no stand where the chains pulled the soil over the seed line. · The only hailed out cotton fields that have had poor stands of sesame have been those with prometryn. On the other hand there have been fields with prometryn that had good stands. It is not known what was different, but researchers have theorized that prometryn does not move as much with the rain as other herbicides and the lack of stands may be related to little rainfall between application and sesame planting. · Prometryn has been used as a POST DIR when the sesame is in the early reproductive phase while it is still possible to get ground rigs into the fields. The prometryn has controlled morningglory and smellmelon (Cucumis melo). The leaves at the bottom of the sesame were affected, but the plants did not die, and there was no effect on the upper canopy. There was no side by side comparison with a control to see the effects on yields, but visually the crop terminated normally. Pyrithiobac (Staple) · Cotton farmers are using more and more pyrithiobac. In 2003 about 400 ha of sesame were planted on hailed out fields that had used pyrithiobac with no stand problems. However, the farmer tried 20 ha and waited before planting the rest because of fears of problems. Pyrithiobac is very water soluble and in 2003 the hail was accompanied by a lot of rain. This herbicide might be a problem with less rainfall. Sethoxydim (Poast) · Sethoxydim has been applied in many stages and in many ways without any damage to the sesame. It has been applied as early as the seedling stage (first true leaf) through late drydown stage. It has been applied by back-pack, ground rig, and from the air. · The only problem with sethoxydim has been that it is not always effective against the johnsongrass if it gets too tall and is no longer growing. Although it is easy to kill johnsongrass from seeds, it is difficult to kill the rhizomes and that johnsongrass may emerge later in the season. Trifluralin (Treflan) · In the first year of planting in Texas, a full cotton label rate (differs in areas) of trifluralin was used, and there was enough of a stand reduction that a half rate (0.5 l/ha) was tried successfully. · The practice in the nurseries was to pre-irrigate, apply the trifluralin at half cotton rate, incorporate it with a harrow, and plant. The trifluralin did a good job controlling grasses and pigweed, but it did not control copperleaf (Acalypha ostryifolia). · In some years in pulling up plants, there was some root pruning, but the plants still matured and looked normal. There was never an attempt to see if the trifluralin had lowered the yield. In the yield sampling in the breeding program, the averages changed from year to year, but the changes could always be correlated to irrigations, fertility, and weather. There was never any reason to suspect that the trifluralin affected the yield in a negative way, but it did affect the yield in a positive way by controlling weeds. · In 1997 there was a heavy rain about 10 days after planting, and the majority of the nursery died off. In pulling up plants that died next to ones that survived, the roots were pruned off the dying plants. The nursery had to be replanted. The author had been cooperating with Grichar

Use only herbicides approved and tested in your area

Appendix 1. Sesame herbicide research by country

Page 40

·

·

· · ·

(2001a), and both felt that metolachlor (Dual) would provide good control with minimum damage to the sesame, and metolachlor has been used since then. Starting back in 1987 there has been sesame planted after hailed out cotton. Trifluralin had been applied prior to planting with different practices ­ some apply it in February/March and others apply it closer to the planting of cotton that ranges from late April to early June. With US insurance policies if there is a hail out prior to a certain date (the date varies with the area), then cotton has to be replanted, but after that any crop can be planted. Most of the sesame planted after hailed out cotton has occurred in the mid June to early July time-frame. There has never been a loss of a sesame stand after hailed out cotton due to trifluralin. It is not known if there is no effect because the trifluralin has been diluted through rains into different ranges of soil, or if the trifluralin loses its potency over time, or the trifluralin is less effective against sesame in warmer soils. In using trifluralin it is critical to place the seed in the moisture below the hot zone of the herbicide. Dry soil with trifluralin has been pulled over the seed line has no effect. There have been problems when there is a rain after the trifluralin has been applied/incorporated and before planting. In these cases, the seed is placed in the hot zone, and the stand can be damaged or even lost. In cold weather, sesame takes longer to germinate and grows even more slowly. Trifluralin appears to damage the plants more when under cool conditions than when it is warmer and the sesame germinates and grows faster. In most uses, trifluralin does a good job in controlling weeds with little effect on sesame; however, there have been fields that were completely lost because of the trifluralin reducing stands. As more and more farmers move to no-till practices, trifluralin will not be as good an option since it has to be incorporated or it will lose its effectiveness. There is very limited data on trifluralin products that can be applied PRE instead of PPI. The only known experiment was done in Argentina by Lanfranconi et al. (2007).

xx-sulfuron products (Accent, Ally, Equip, Exceed, Finesse, Glean, Peak, Envoke) · There are many wheat farmers that apply sulfuron products late in the wheat crop to control broadleaf weeds. There are been mixed results in planting sesame after these products. In some years there are good stands of sesame and in other years there are poor stands. Even with no herbicides, planting sesame after disked in wheat can be a problem in some years when the disking operation reduces the moisture and there are not enough replacement rains. Therefore, it is difficult to really know if the herbicides or the lack of moisture were the problem. However, some farmers in the mid 1990s found that they had good stands of sesame on fields where they had not used the sulfuron products and poor stands where they had used them.

Use only herbicides approved and tested in your area

Appendix 2. Herbicides by trade name

Page 1

The following table is in trade name order. `X' indicates that there has been research done on that active ingredient. `Com' indicates that the active ingredient is used in commercial sesame fields somewhere in the world.

Active ingredient Dichlormate Proatryne Sirmate Atrazine Endothal Nicosulfuron Bentazon Linuron Monolinuron Trifluralin Carfentrazone Naptalam (NPA) Alachlor Alachlor Metolachlor Metsulfuron Triasulfuron Chloramben Diethatyl Sulfentrazone Flufenacet Benefin Bentazon Fluchloralin Glufosinate Amiprophosmethyl Bentazon Phenmediphan Imazamox Acifluorfen Thiobencarb Flumioxazin Diflufenican Glyphosate Bromoxynil 2,4D-B Diethylacetanilide Imazapic Mesotrione Prometryn Dichlobenil Fluthiacet-methyl Flumioxazin Chlorpropham (CIPC) Dicamba Chlorimuron Dinitramine Trade name PRE paper X X X X X X Com X Com X Com Com Com X X X X X X X Com X X X X X X X X Com X X X X X X X X X Com X X X X X X X X X X OP POST paper Out of production

Aatrex Accelerate Accent Adagio Afalon Afesin Agriflan Aim Alanap Alanox Alar Allfire Ally Amber Amiben Antor Authority Axiom Balan Basagran Basalin Basta Bay-NTN 6867 Bendioxide Betanal Beyond Blazer Bolero Broadstar Brodal Buccaneer Buctril Butyrac C-10725 Cadre Callisto Caparol Casoron CGA Chateau Chloro-IPC Clarity Classic Cobex

X X X X X

X X X X

OP

X OP

Use only herbicides approved and tested in your area

Appendix 2. Herbicides by trade name

Page 2

Active ingredient Lactofen Metolachlor + prometryn Clomazone Fluometuron Sesone Ethalfluralin Benfuresate Chlorothal Perfluidone Napropamide Dinoseb Diuron Diflufenzopyr Diuron Flufenacet + metribuzin Metolachlor S-Metolachlor Glyphosate Diphenamid Oxasulfuron Piraflufen ethyl Diphenamid Bentazon Trifloxysulfuron EPTC Foramsulfuron + Iodosulfuron Pyraflufen-ethyl Prosulfuron Glufosinate Chlorsulfuron + Metsulfuron Cloransulam Fomesafen Dimethenamid Chlorpropham (CIPC) Fluazifop-P Metolachlor + metobromuron Oxasulfuron Prometryn Ametryn Atrazine Chlorsulfuron Oxyfluorfen Paraquat Pendimethalin Norea Diclofop Glufosinate Alachlor Diuron Pronamide Fluometuron Fluometuron

Trade name Cobra Codal Command Cotoran Crag Curbit Cyperal Dacthal Destun Devrinol Dinitro Direx Distinct Diurol Domain Dual Dual Magnum Durango Dymid Dynam Ecopart Enide Entry Envoke Eptam Equip ET Exceed Finale Finesse FirstRate Flex Frontier Furloe Fusilade Galex GCA Gesagard Gesapax Gesaprim Glean Goal Gramoxone Herbadox Herban Hoelin Ignite Intrro Karmex Kerb Kotoran Lanex

PRE paper X X Com X X X X X X X Com Com X Com Com Com X

POST paper X

Out of production

OP Com X Com Com Com Com X X X X X X X X X X X X

OP

X

OP

X

X X X X X

Com Com X X X X X Com X X Com Com X Com Com X X X X X Com OP X X Com OP

Use only herbicides approved and tested in your area

Appendix 2. Herbicides by trade name

Page 3

Active ingredient Alachlor Linuron + Diuron Bentazon Pyridate Metribuzim Glufosinate Linuron Clopyralid Linuron Rimsulfuron Asulam S-Metolachlor Propazine Propazine Bifenox Monuron Isopropaline Napropamide Metobromuron Prosulfuron Pendimethalin Nitralin Bentazon Sethoxydim Bensulide Fluorodifen Profluralin Dinoseb Flumetsulam Simazine Methazole Chlorothal Pendimethalin Pendimethalin Imazethapyr Sulfonamide Carbothioate Propachlor Allidochlor (CDAA) Fomesafen Glufosinate Oxadiazon Glyphosate Glyphosate Clethodim Metribuzim Metribuzim Sethoxydim Chlorothal Norflurazon Ethalfluralin Diclosulam

Trade name Lasso, Lazo Layby Pro Leader Lentagran Lexone Liberty Linurex Lontrel Lorox Matrix MB-9057 Medal Milocep Milogard Modown Monurex Paarlan Pamid Patoran Peak Pendimax Planavin Pledge Poast Prefar Preforan Pregard Premerge Preside Princep Probe Prothal Prowl Prowl H2O Pursuit Python R-12001 Ramrod Randox Reflex Rely Ronstar Roundup RT3 Select Max Sencor Sencorex Sertin Shamrox Solicam Sonalan Spider

PRE paper Com X

POST paper X X X

Out of production

X Com X Com X X Com X X X X X Com

X X X X Com X Com X OP

OP X Com OP X Com

X X X X X X X X Com Com X X X X X

OP OP X

Com Com X

X Com Com X X

X X X Com Com Com

Com X X X X

X

Use only herbicides approved and tested in your area

Appendix 2. Herbicides by trade name

Page 4

Active ingredient Propanil Pyrithiobac Fluroxypyr Pendimethalin Diclosulam Flumioxazin Prometryn Linuron Monuron Chloroxuron Pebulate Nitrofen Glyphosate Pyridate Trifluralin Trifluralin + diphenamid Methabenthiazuron Flumioxazin Haloxyfop Vernolate Bromoxynil Fenoxaprop Norflurazon DMPA

Trade name Stam-F-34 Staple Starane Stomp Strongarm Sumisoya Suprend Teliron Telvar Tenoran Tillam TOK E-25 Touchdown Tough Treflan Trefmid Tribunil Valor Verdict Vernam Weedex Whip Zorial Zytron

PRE paper X X Com X X X Com X X X X Com Com X X X

POST paper X Com X X X X

Out of production

OP OP OP Com

X X Com X

X X X

Use only herbicides approved and tested in your area

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