Efficacy of Registered and Experimental Insecticides for Control of Corn Earworm and European Corn Borer on Corn Under Natural Infestation, 1996

Abstract

Abstract Corn was planted at the University of Illinois Vegetable Crops Farm, Champaign, IL in rows 30 inches wide on 26 Jun. A RCB design was used, and each treatment was replicated four times, with two untreated checks per replicate. These two controls within each block were averaged for analysis. Each plot was 4 rows wide X 50 ft long. Insecticides were applied to the middle rows of each plot; the two outside rows were left untreated, leaving two untreated rows between each treatment. Treatments were applied with a modified John Deere 6000 high-clearance sprayer with a rear-mounted boom. Three Conejet (TXVS-8) hollow cone nozzles per row; two attached to drops allowing spray to be directed towards the ear zone and one nozzle positioned directly over the row. Sprays were delivered with a compressed-air system calibrated to deliver 29.5 gpa at 40 psi and 2.5 mph. A pre-silk application of all treatments was made on 15 Aug, in response to extremely high ECB moth flights. Silk sprays were applied on 20, 24, and 28 Aug; 1 and 6 Sep, beginning at 12% silk. At maturity, twenty-five ears were harvested per treatment from each replication (100 ears/treatment) on 10 Sep. Ears were husked and evaluated and the number of damaged ears, pest species, larval size and location of ear damage (tip or side) were recorded for each ear.