Bentazon Translocation and Metabolism in Soybean and Navy Bean

Abstract

Following foliar application of14C-bentazon [3-isopropyl-1H-2,1,3-benzothiadiazin-(4)3H-one 2,2-dioxide], a promising selective postemergence herbicide for the control of broadleaf weeds in soybean [Glycine max(L.) Merr.] and navy bean (Phaseolus vulgarisL.), the movement of the14C-label was primarily acropetal in both species, with some basipetal movement. Metabolism was more rapid in the trifoliate navy bean leaf than in the unifoliate navy bean leaf and the trifoliate soybean leaf. Prior treatment with several other herbicides did not decrease metabolism of bentazon in navy bean. The metabolites in navy bean and soybean appeared similar. Four apparent14C-conjugates were isolated from soybean plants harvested at full maturity.