Insecticide Tests for Control of the Western Bean Cutworm

Little has been published on insecticidal control of the western bean cutworm on beans and corn. This report summarizes results of tests in southern Idaho from 1950 to 1980. Of 53 chemicals tested in the laboratory, 24 showed effectiveness approximately equal to or better than DDT or carbaryl, which were used as standards. Of 26 materials applied as sprays to beans with ground equipment, 7 that were tested most extensively indicate effectiveness equal to or better than carbaryl, and 9 tested less extensively .indicate a high degree of effectiveness. Of those materials applied by air to sweet corn, permethrin provided almost perfect control, Three formulations of carbaryl did not differ significantly in performance in individual tests, but the newer formulations appear to be an improvement. The efficacy of insecticides decreased with delay in time of application in relation to peak moth flight due to a combination of increased size of larvae and increased foliage density.