The Granule Formulation of Selective Rice Herbicide Cyhalofop Butyl

Abstract

Cyhalofop butyl, [R-(+)-n-butyl-2-(4-(2-fluoro-4-cyanophenoxy) phenoxy) propionate] is a selective rice graminicide, which can control up to the 5-6 leaf stage of Echinochloa crus-galli by foliar application. Japanese agricultural practices requires development of a granule formulation of cyhalofop butyl; however, the conventional type of extruded granule of the herbicide showed unacceptable bioefficacy. Different commercial ester products on KCl core granules were therefore evaluated in greenhouse trials and field trials in Japan to improve this bioefficacy. Among them, ditridecyl phthalate enhanced the efficacy significantly over that of water treatment of cyhalofop butyl EC formulation. Employment of di-tridecyl phthalate contributed to the high concentration of the graminicide on the water surface, prolonged its half life on hydrolysis and enhanced its uptake into plants. These results suggested that cyhalofop butyl granules containing ditridecyl phthalate would be an effective way to maximize bioefficacy of this herbicide.