Spray drift to unintended areas is more of a concern as applications of nonselective herbicides associated with herbicide-resistant crops and the proximity of residential land to agricultural land increase. This research evaluated the benefit of three commercial drift control agents for effectiveness in reducing drift in 19 to 24 km/h wind and their potential effect on weed control. The drift control agents were added to a spray mixture of glyphosate at 0.8 kg ae/ha applied in 140 L/ ha and applied with either flat-fan or flood nozzles. None of the drift control agents reduced drift compared with the spray mixture without drift control agent over a distance of 6 m, as measured by water-sensitive cards or grain sorghum bioassay, regardless of nozzle type used. In a separate study, drift control agents did not reduce the weed control of glyphosate or acifluorfen.
Nomenclature: Acifluorfen; glyphosate; grain sorghum, Sorghum bicolor (L.) Moench.
Additional index words: Adjuvants, bioassay, crop injury, flat-fan nozzles, flood nozzles, Glycine max, off-site movement, soybean, spray drift.
Abbreviation: WS, water sensitive.