AERIAL SPRAY DRIFT FROM DIFFERENT FORMULATIONS OF GLYPHOSATE

Glyphosate and similar herbicides have facilitated low and no-till production systems through more effective management of winter weeds before planting spring-seeded crops. Crop cultivars tolerant to specific herbicides are also more readily available. Increased use of these systems and their requirements for timely herbicide applications have increased the acreage of herbicides applied by aircraft. Manufacturers of glyphosate have also made some changes in the product formulations in an effort to provide improved efficacy and convenience. A combination of these and other factors have increased the incidence and raised awareness of spray drift from aerial applications of glyphosate. This study was conducted to provide information in response to those concerns. Four spray mixes of glyphosate from three different formulations were included in an extensive field study to determine relative drift propensity of the spray mixes from the different formulations. There were no meaningful differences in spray deposition, spray drift, and atomization in a wind tunnel between the glyphosate formulations of Roundup® and Roundup Ultra®.