POTENTIAL DRIFT AND INJURY OF HERBICIDES SPRAYED IN A WIND TUNNEL

ABSTRACT The possibility of synthetic auxin applications in crops increases the risk of injury to sensitive plants. The aim of this study was to quantify the drift of herbicides sprayed in a wind tunnel and the injury in cotton plants. The experimental design was a completely randomized design with five treatments and four replications. The tested spray solutions were dicamba (0.250 L c.p. ha−1), glyphosate (0.625 L c.p. ha−1), 2,4-D (0.250 L c.p. ha−1), glyphosate + 2,4-D (0.625 L c.p. ha−1 + 0.250 L c.p. ha−1), and glyphosate + dicamba (0.625 L c.p. ha−1 + 0.250 L c.p. ha−1). Drift was quantified in a wind tunnel, collected at distances of 5, 10, and 15 m in relation to the spray tip. Cotton plants were placed in the same wind tunnel and the injury was visually evaluated for at 3, 7, and 15 days after application (DAA). The addition of glyphosate to dicamba and 2,4-D potentiated the drift from 5 m. At 10 and 15 m, dicamba and 2,4-D in isolation had the lowest drift potential. At 5 m, the injury is higher than at other distances regardless of the spray solution. At 10 m, 2,4-D in isolation presented the highest injury when compared to dicamba in isolation at 7 and 15 DAA. At 10 and 15 m, the addition of glyphosate to dicamba enhances the injury in cotton plants and herbicide mixtures do not differ from each other in relation to injury.