Effects of Tank-Mix Combinations of Non-Selective Foliar and Selective Soil-Applied Herbicides on Three Weed Species

Abstract

Greenhouse experiments were established to investigate the effects of tank-mixing glyphosate, paraquat, or glufosinate with metribuzin plus chlorimuron, imazaquin, or metribuzin on entireleaf morningglory, sicklepod, and johnsongrass control. Antagonism was the most frequent interaction, and usually occurred when the lower rates of non-selective foliar-active herbicides were used in tank mixtures with selective soil-active herbicides. Antagonism occurred on all species when 180 g ai/ha paraquat was tank-mixed with 90 g ai/ha metribuzin plus 15 g ai/ha chlorimuron. When the rates of non-selective herbicide were increased, antagonism was usually overcome. Antagonism also occurred on entireleaf morningglory control when 210 g ai/ha glyphosate was tank-mixed with 90 g/ha metribuzin plus 15 g/ha chlorimuron or 36 g ai/ha imazaquin. When lower rates of paraquat or glufosinate were tank-mixed with 210 g/ha metribuzin, antagonism also occurred. Less antagonism was noted with glufosinate.