First Generation European Corn Borer Control, 1986

Abstract Naturally infested late whorl stage, yellow field corn, located near Mt. Ayr, Ringgold Co., IA was aerially treated on 19 Jun. Seven insecticides and 1 untreated check were arranged in a randomized complete block design and replicated 4 times. Plots measured 30 rows by approximately 400 yd. Weather conditions were clear with a temperature of 88°F, relative humidity of 53%, and a light, intermittent breeze from the west, southwest. All applications were made between 1:45 and 4:00 p.m. by flying both north and south on north-south rows. Pretreatment counts made on 14 Jun consisted of examining 20 plants from each of 20 randomly selected locations throughout the study site. The number of plants with shot-hole damage were recorded. Four plants from each location were dissected and the number of European corn borer (ECB) larvae recorded. Insecticide efficacy was evaluated on 22 Jul by removing 30 selected plants from each plot, dissecting them and recording the number of ECB cavities per plant. Plants used in the efficacy evaluation were selected from the ninth row in from the east side of each plot. Individual plants were selected by walking into the field 30 paces from the turn rows, then cutting every tenth plant. Efficacy data were analyzed using an AOV. The means were ranked and separated (P = 0.05) using Duncan's Multiple Range Test. All data were normalized before analysis with a SQRT (X = 1.0) transformation.