Selectivity of Dinoseb in an Isoparaffinic Oil Carrier

Abstract

The relative susceptibility of 40 plant species to postemergence applications of 2-sec-butyl-4,6-dinitrophenol (dinoseb) in isoparaffinic oil was determined. Peanuts (Arachis hypogaeaL. ‘Holland Virginia 56R’), with an I50of greater than 2.24 kg/ha, were the most tolerant, and johnsongrass (Sorghum halepense(L.) Pers.) seedlings, with an I50of 0.011 kg/ha, were the most susceptible. This is greater than a 200-fold difference in susceptibility, due primarily to internal tolerance, because penetration differences were reduced with the isoparaffinic oil carrier. Legumes generally were the most tolerant, and grasses ranged from tolerant to the most susceptible. Several species, primarily grasses, showed greater than 25% inhibition of shoot fresh weight from the isoparaffinic oil carrier alone.