In-Whorl Treatments for Fall Armyworm and Second Brood European Corn Borer in Late-Planted Field Corn, 1986

Abstract

Abstract 'Pioneer 3147' corn was planted on 15 Jun and 1 Jul at the Highland Rim Experiment Station, Springfield. Fourteen treatments replicated 4 times were arranged in a randomized complete block design for each planting. Plots were 30 ft × 4 rows with 5 ft alleys between blocks. Rows were spaced 40 inches apart with 45 plants/30 row ft. The 2 middle rows were evaluated for whorl damage. The second row was harvested for ensilage yields. Liquid formulations were applied using 2.5 gal compressed C02 sprayers at 30 psi and 30 gal/acre. Granular insecticides were applied with shaker jars. In the first planting, one insecticide application was made on 16 Jul when 65% of the plants were infested with an average of 1.86 larvae/plant. Ensilage yield was determined on 26 Sep at 49.3% moisture. In the second planting, the first insecticide application was made on 31 Jul when 72% of the plants were infested with an average of 3.76 larvae/plant; the second application was made on 12 Aug. Ensilage yield was determined on 9 Oct at 36.4% moisture. Newly damaged whorls by the fall armyworm were counted one week after each application. European corn borer stalk feeding counts (average number of busal tunnels/45 stalks) were made at harvest. Soil type was Dixon silt loam, 2-5% slope. Total rainfall for the growing season was 8.96 inches.