Effect of Adjuvants on Herbicide Efficacy in Controlling Weeds in Wheat

Abstract

Two adjuvants, Triton 11 XE (Isoctyl phenyl polyethoxy ethanol) and urea were tank mixed with four herbicides, methabenzthiazuron [N-(benzothiazol-2-yl)N,N′-dimethyl urea] at 1.0 and 1.5 kg ai/ha, terbutryn [N-(1,1-dimethylethyl)-N′-ethyl-6-(methylthio)-1,3,5-triazine-2,4-diamine] at 0.50 and 0.75 kg/ha, metoxuron [N-3-chloro-4-methoxyphenyl)N,N-dimethylurea] at 1.0 and 1.75 kg/ha, and isoproturon [(N-(4-isopropylphenyl)-N,N-dimethylurea] at 0.50 and 0.75 kg/ha and applied to weeds in wheat. Metoxuron reduced weed dry matter by 90% over a 2-yr period. Isoproturon, terbutryn, and methabenzthiazuron reduced weed dry matter by 82%. Tank-mixing of Triton 11 XE at 0.5% (v/v) with metoxuron at 1.0 kg ai/ha, terbutryn at 0.5 kg/ha, isoproturon at 0.5 kg/ha, and methabenzthiazuron at 1.0 kg/ha reduced weed density and biomass by 52 to 67% and enhanced grain yield by 33% over herbicide alone. None of the herbicides had any significant interaction with adjuvants in terms of weed control and grain yield.