Submitted to: International Symposium on Adjuvants for Agrochemicals
Publication Type: Proceedings
Publication Acceptance Date: 7/1/1998
Publication Date: N/A
Citation: Interpretive Summary: Research was conducted to determine the effect of eight experimental drift retarding adjuvants on weed control, spray pattern, and spray droplet size. Efficacy on prickly sida and barnyardgrass was often reduced by the addition of drift retarding adjuvants, but was never enhanced. Three of the drift reducing adjuvants adversely affected spray patterns by reducing the width of the spray pattern, resulting in non-uniform spray patterns. Spray droplet size was increased varying degrees with drift retarding adjuvants, therefore potential for drift reduction varied for the eight drift retarding adjuvants. Effectiveness decreased for six of the eight adjuvants when subjected to repeated passes through a centrifugal pump, only two adjuvants were not adversely affected by the pumps shearing action on the liquid.
Technical Abstract: Eight experimental drift reducing adjuvants were evaluated to determine their effect on weed control, spray pattern with water alone, spray pattern with glyphosate (Roundup Ultra) and spray volume in droplets less than 105 microns when subjected to repeated passes through a centrifugal pump. Weed control with and without drift reducing adjuvants was 62 to 73 percent and 77 to 92 percent respectively for prickly sida and barnyardgrass. Herbicidal efficacy was not increased when drift reducing adjuvants were added, but resulted in a reduction in weed control by as much as 15 percent with some adjuvants. Addition of glyphosate alone had no effect on spray pattern, whereas three of the drift reducing adjuvants caused significant distortion in spray patterns with water alone and with glyphosate added. The other five adjuvants had little effect on spray pattern with water alone or when glyphosate was added. Effectiveness in reducing the spray volume in droplets less than 105 microns decreased for six of the adjuvant when subjected to repeated passes through a centrifugal pump.