Foliar Insecticide Evaluation for Control of Corn Earworm on Sweet Corn, 1994

‘Silver Queen’ sweet corn was planted on 24 May at the North Alabama Horticulture Substation in Cullman, Alabama. Treatment plots were 6 rows, each 10 meters long, replicated four times in a randomized complete block design. The four middle rows of each plot were sprayed with insecticides beginning at “tassel push", when the tassels were first observed growing up from the whorl, and on a 3-4 day schedule throughout the silking period until harvest. Sprays were applied on 19, 22, 26, 29 July, and on 1 and 4 Aug. Spray application was made by a self-propelled high-clearance sprayer with one hollow cone nozzle over the row and 1—6 nozzles on drop extension tubes on either side of the row (additional nozzles ere added as corn height increased). Spray volume remained constant on all spray dates at 80 gal/acre. Treatment effectiveness was determined at harvest (8 Aug) by examination of 25 randomly-picked ears per plot (100 ears per treatment) for CEW feeding damage to the ear tips. Worm feeding damage not associated with the ear tip was classified as “side damage” (assumed to be caused by other lepidopterous species). Ears were considered unmarketable if CEW damage to the ear extended 38 mm (1.5 inches) beyond the tip of the ear, or if “side damage” was present.