**Abstract**

Harvest aids are traditionally used to desiccate weeds to improve crop quality and harvest efficiency. Field studies were conducted in Texas to determine the effect of harvest aids (glyphosate, diquat-dibromide, glufosinate-ammonium, and carfentrazone-ethyl) on sesame drydown and yield. The objective was to identify one or more harvest aids that could (1) accelerate drydown, (2) burn-down green weeds, (3) even up a field with varying levels of drydown, (4) stop regrowth, (5) stop vivipary, and (6) prepare to plant a new crop. Other than diquat-dibromide, the herbicides were chosen based on the effect on weeds in other crops. The plan was to apply the herbicides 1 week before physiological maturity (PM), at PM, and 1 week after PM. However, sesame maturity is very sensitive to ground moisture, ambient temperature, and relative humidity. The weather was different in all trials and some stages could not be completed. In two cases, the trials had to be abandoned; however, certain patterns emerged. All the herbicides accelerated drydown compared to the untreated check. Diquat-dibromide and glufosinate-ammonium dried sesame faster than glyphosate and carfentrazone-ethyl. The higher rates of the herbicide dried down the sesame faster than the low rate. Although there were some differences in yields across the three application periods, there was no consistent pattern.

**Keywords:** carfentrazone-ethyl, diquat-dibromide, glyphosate, glufosinate-ammonium, and sesame yield

#### **1. Introduction**

After a crop has matured and completed seed fill, there is no weather event that can increase yield, but there are many weather events that can decrease yield and crop quality. Getting the crop out of the field as soon as possible is a critical part of recovering what has taken months to nurture and develop. Harvest aids traditionally are used to desiccate weeds to improve crop quality and harvest efficiency [1].

In recent years, the use of harvest aids has become important in production of early maturing soybean (*Glycine max* L.) in the states of Kentucky, Mississippi, Missouri, and Tennessee. Soybean leaf retention and presence of green stems and/or green pods in fields where soybean seed are mature (green plant malady) can delay or prevent harvest [2]. Philbrook and Oplinger [3] reported that soybean seed yield loss increased linearly at a rate of 0.2% per day as harvest was delayed out to

42 days. Therefore, harvest aids play an important role in desiccating the crop and accelerating harvest.

operation; managing maturity, allowing earlier harvest; increased air movement through the crop canopy, which facilitates quicker drying to allow picking to begin earlier in the day; reducing moisture; and improving storage in modules. There are many products used for defoliation in cotton including tribufos, carfentrazoneethyl, carfentrazone-ethyl + fluthiacet-methyl, pyraflufen-ethyl, saflufenacil, thidiazuron, thidiazuron + diuron, and ethephon + cyclanilide. Glyphosate is used for killing weeds in the crop while paraquat-dichloride and sodium chlorate are

*Effects of Harvest Aids on Sesame (*Sesamum indicum *L.) Drydown and Maturity*

Zotarelli et al. [15] reported carfentrazone-ethyl, diquat-dibromide, glufosinateammonium, pyraflufen-ethyl, and pelargonic acid are used for vine killing in potato (*Solanum tuberosum* L.) harvest. Killing the vine can improve the quality of some potatoes, but used incorrectly, the harvest aids may reduce the quality. Fleury [16] reported diquat-dibromide, glyphosate, carfentrazone-ethyl, and carfentrazoneethyl + glyphosate are used to desiccate chickpeas (*Cicer arietinum* L.) in Canada. Proper size and color are critical for marketing chickpeas; thus, the crop needs to be mature before using harvest aids. Direct harvest is preferred over swathing because the peas will not cure well in the swath. The cooler nights and shorter days increase the number of days to drydown. Frosts may desiccate the crop without the use of harvest aids. Diquat-dibromide and carfentrazone-ethyl will accelerate drydown while glyphosate will not accelerate drydown. Glyphosate and carfentrazone-ethyl should not be used on chickpea that is to be used for planting seed since they will

In reviewing the information on other crops, there are certain points that pertain

to using harvest aids or dessicants that have been studied for sesame (*Sesamum indicum* L.): glyphosate, paraquat-dichloride, diquat-dibromide, glufosinate-

• Harvest aids accelerate the harvest of a crop thereby reducing losses from

• Harvest aids work better in warm, dry weather than in cold, cloudy, rainy weather. Depending on the temperatures and length of time in subfreezing weather, frosts will kill the sesame and not require harvest aids. Frost generally does not harm seed quality; however, hard freezes may affect the quality. M.L. Kinman (personal communication, 1982) related that in Nebraska a hard freeze killed sesame. When the seed was harvested, it appeared normal, but within a few days the free fatty acids increased quickly rendering the crop unmarketable. The effects of the cold are dependent on the length of time with freezing temperatures, the temperature itself, and the moisture in the seed.

• Harvest aids can help kill weeds facilitating combining and producing a drier crop. In the USA, harvesting sesame during 6% moisture is critical for storage in silos. Sesame has approximately 50% oil, and under high moisture, like other oilseeds, can catch fire in silos. Most of the world can harvest sesame at higher

harvesting sesame seeds that are 6% moisture, if there are moist weed stems,

moisture levels because the seed is stored in jute bags that breathe. In

• Harvest aids should be applied at or after PM to avoid crop and/or quality loss. Harvest aids will not mature immature seed. The authors have observed that the harvest aids stop all growth on the sesame plant and appear to freeze the seed fill; however, this has not been confirmed in controlled experiments. Although the seed will not increase in weight, it is a living organism and may

ammonium, carfentrazone-ethyl, and pyraflufen-ethyl.

put on seed color and dry the placenta attachment.

used for desiccation.

*DOI: http://dx.doi.org/10.5772/intechopen.91011*

affect the germination.

inclement weather.

**207**

Fromme et al. [4] reported using harvest aids to harvest sorghum [*Sorghum bicolor* (L.) Moench] at or after maturity. Harvest aids provide the following advantages: accelerates harvest minimizing weather related damage; prevents or stops seed sprouting; kills the sorghum plant, which is a perennial; provides more efficient and faster threshing; dries out nonproductive suckers and tillers which can delay harvest; reduces differences in harvest maturity across a field; kills late-season weeds; and reduces weed matter in the grain. The application must wait until physiological maturity (PM) to avoid sacrificing yield and reducing test weight. There are three products labelled for use in sorghum: sodium chlorate, glyphosate, and carfentrazone-ethyl. Sodium chlorate provides leaf desiccation but will not kill the plant. Harvest must be timely to avoid regrowth. Desiccation is slowed with low temperatures. Glyphosate is a systemic that will kill the plant and weeds but not accelerate maturity. Carfentrazone-ethyl kills weeds, particularly *Ipomoea* spp. Trostle and McGinty [5] reported good results with the same harvest aids plus diquat-dibromide, which is used only for seed hybrid grain sorghum. Bean [6] reported sodium chlorate is also used for harvesting seed grain sorghum. In North Texas, frost will kill plants without using a harvest aid.

Armstrong [7] reported metsulfuron, 2,4-D, dicamba, glyphosate, and carfentrazone-ethyl and combinations are used as harvest aids for wheat (*Triticum aestivum* L.) to help reduce the amount of green weeds running through the combine. The application must be done after the wheat is mature and different harvest intervals are necessary to allow some of the seed from the weeds to dry so they can be separated by the combine fan. Johnson et al. [8] reported dicamba, glyphosate, and 2,4-D could be used on wheat; however, dicamba and 2,4-D may affect a subsequent double crop. Glyphosate should not be used for seed wheat.

In peanuts (*Arachis hypogaea* L.), Jordan [9] recommended applying carfentrazone-ethyl within 7 days of optimum pod maturity and digging and vine inversion to control *Ipomoea,* which can be a problem at harvest*.* Chaudhari and Jordan [10] reported carfentrazone-ethyl and pyraflufen-ethyl applied 2 weeks before digging did not reduce the yield or quality of peanuts and controlled *Ipomoea*. Grichar et al. [11] reported 7–52% injury and 4–26% stunting of peanut when carfentrazone-ethyl and pyraflufen-ethyl were applied 35–56 days after planting. They also reported peanut tolerance to carfentrazone-ethyl and pyraflufen-ethyl was cultivar dependent.

Hardke [12] reported sodium chlorate is used as a harvest aid on rice (*Oryza sativa* L.) to accelerate drying in order to accelerate harvest time. Diquat-dibromide, glyphosate, and saflufenacil are used to desiccate canola (*Brassica napus* L.) in Canada [13]. The crop is swathed or harvested direct by using harvest aids to avoid killing frosts that damage the quality of the canola. As opposed to swathing, the advantages of direct harvest are reduced labor and equipment requirements. Diquat-dibromide is a desiccant that will accelerate drydown (4–7 days) but will not control weeds. Glyphosate can dry down canola in warm, sunny days (1–3 weeks), but the primary function is to control weeds. Saflufenacil has some of the functions of diquat-dibromide and glyphosate in terms of contact and systemic activity but none of the harvest aids will hasten maturity and they need to be applied at or after maturity.

Dodds et al. [14] reported harvest aids are used for cotton (*Gossypium hirsutum* L.) defoliation, weed control, and desiccation. All are dependent on the field conditions, weather conditions, and require multiple applications. Defoliation provides the following benefits: removing leaves; eliminating the main source of stain and trash; better lint grades; preventing boll rot; faster and more efficient picker

#### *Effects of Harvest Aids on Sesame (*Sesamum indicum *L.) Drydown and Maturity DOI: http://dx.doi.org/10.5772/intechopen.91011*

operation; managing maturity, allowing earlier harvest; increased air movement through the crop canopy, which facilitates quicker drying to allow picking to begin earlier in the day; reducing moisture; and improving storage in modules. There are many products used for defoliation in cotton including tribufos, carfentrazoneethyl, carfentrazone-ethyl + fluthiacet-methyl, pyraflufen-ethyl, saflufenacil, thidiazuron, thidiazuron + diuron, and ethephon + cyclanilide. Glyphosate is used for killing weeds in the crop while paraquat-dichloride and sodium chlorate are used for desiccation.

Zotarelli et al. [15] reported carfentrazone-ethyl, diquat-dibromide, glufosinateammonium, pyraflufen-ethyl, and pelargonic acid are used for vine killing in potato (*Solanum tuberosum* L.) harvest. Killing the vine can improve the quality of some potatoes, but used incorrectly, the harvest aids may reduce the quality. Fleury [16] reported diquat-dibromide, glyphosate, carfentrazone-ethyl, and carfentrazoneethyl + glyphosate are used to desiccate chickpeas (*Cicer arietinum* L.) in Canada. Proper size and color are critical for marketing chickpeas; thus, the crop needs to be mature before using harvest aids. Direct harvest is preferred over swathing because the peas will not cure well in the swath. The cooler nights and shorter days increase the number of days to drydown. Frosts may desiccate the crop without the use of harvest aids. Diquat-dibromide and carfentrazone-ethyl will accelerate drydown while glyphosate will not accelerate drydown. Glyphosate and carfentrazone-ethyl should not be used on chickpea that is to be used for planting seed since they will affect the germination.

In reviewing the information on other crops, there are certain points that pertain to using harvest aids or dessicants that have been studied for sesame (*Sesamum indicum* L.): glyphosate, paraquat-dichloride, diquat-dibromide, glufosinateammonium, carfentrazone-ethyl, and pyraflufen-ethyl.


42 days. Therefore, harvest aids play an important role in desiccating the crop and

*Pests, Weeds and Diseases in Agricultural Crop and Animal Husbandry Production*

Fromme et al. [4] reported using harvest aids to harvest sorghum [*Sorghum bicolor* (L.) Moench] at or after maturity. Harvest aids provide the following advantages: accelerates harvest minimizing weather related damage; prevents or stops seed sprouting; kills the sorghum plant, which is a perennial; provides more efficient and faster threshing; dries out nonproductive suckers and tillers which can delay harvest; reduces differences in harvest maturity across a field; kills late-season weeds; and reduces weed matter in the grain. The application must wait until physiological maturity (PM) to avoid sacrificing yield and reducing test weight. There are three products labelled for use in sorghum: sodium chlorate, glyphosate, and carfentrazone-ethyl. Sodium chlorate provides leaf desiccation but will not kill the plant. Harvest must be timely to avoid regrowth. Desiccation is slowed with low temperatures. Glyphosate is a systemic that will kill the plant and weeds but not accelerate maturity. Carfentrazone-ethyl kills weeds, particularly *Ipomoea* spp. Trostle and McGinty [5] reported good results with the same harvest aids plus diquat-dibromide, which is used only for seed hybrid grain sorghum. Bean [6] reported sodium chlorate is also used for harvesting seed grain sorghum. In North

Texas, frost will kill plants without using a harvest aid.

pyraflufen-ethyl was cultivar dependent.

maturity.

**206**

Armstrong [7] reported metsulfuron, 2,4-D, dicamba, glyphosate, and carfentrazone-ethyl and combinations are used as harvest aids for wheat (*Triticum aestivum* L.) to help reduce the amount of green weeds running through the combine. The application must be done after the wheat is mature and different harvest intervals are necessary to allow some of the seed from the weeds to dry so they can be separated by the combine fan. Johnson et al. [8] reported dicamba, glyphosate, and 2,4-D could be used on wheat; however, dicamba and 2,4-D may affect a subsequent double crop. Glyphosate should not be used for seed wheat. In peanuts (*Arachis hypogaea* L.), Jordan [9] recommended applying carfentrazone-ethyl within 7 days of optimum pod maturity and digging and vine inversion to control *Ipomoea,* which can be a problem at harvest*.* Chaudhari and Jordan [10] reported carfentrazone-ethyl and pyraflufen-ethyl applied 2 weeks before digging did not reduce the yield or quality of peanuts and controlled *Ipomoea*. Grichar et al. [11] reported 7–52% injury and 4–26% stunting of peanut when carfentrazone-ethyl and pyraflufen-ethyl were applied 35–56 days after planting. They also reported peanut tolerance to carfentrazone-ethyl and

Hardke [12] reported sodium chlorate is used as a harvest aid on rice (*Oryza sativa* L.) to accelerate drying in order to accelerate harvest time. Diquat-dibromide, glyphosate, and saflufenacil are used to desiccate canola (*Brassica napus* L.) in Canada [13]. The crop is swathed or harvested direct by using harvest aids to avoid killing frosts that damage the quality of the canola. As opposed to swathing, the advantages of direct harvest are reduced labor and equipment requirements. Diquat-dibromide is a desiccant that will accelerate drydown (4–7 days) but will not control weeds. Glyphosate can dry down canola in warm, sunny days (1–3 weeks), but the primary function is to control weeds. Saflufenacil has some of the functions of diquat-dibromide and glyphosate in terms of contact and systemic activity but none of the harvest aids will hasten maturity and they need to be applied at or after

Dodds et al. [14] reported harvest aids are used for cotton (*Gossypium hirsutum* L.) defoliation, weed control, and desiccation. All are dependent on the field conditions, weather conditions, and require multiple applications. Defoliation provides the following benefits: removing leaves; eliminating the main source of stain and trash; better lint grades; preventing boll rot; faster and more efficient picker

accelerating harvest.
