Effectiveness of a New Safener for Protecting Sorghum (<i>Sorghum bicolor</i>) from Metolachlor Injury

Abstract

A herbicide safener, CGA-43089 [α-(cyanomethoximino)-benzacetonitrile], has been discovered which will allow the safe use of metolachlor [2-chloro- N -(2-ethyl-6-methylphenyl)- N -(2-methoxy-1-methylethylacetamide] in grain sorghum [ Sorghum bicolor (L.) Moench]. Experiments revealed that sorghum is protected from injury by metolachlor when it is applied at rates as high as 4 kg/ha. Better protection was achieved when sorghum seed were treated directly with the safener than when it was mixed with the herbicide. A CGA-43089 rate of 1.25 to 1.5 g per kg of sorghum seed was adequate for protection. Sorghum tolerance to metolachlor was maintained with CGA-43089 when metolachlor was combined with several s -triazine herbicides. Metolachlor effectively controlled several annual grasses with an increase in sorghum yield.