European Corn Borer Control with Microbial and Conventional Insecticides, 1991

Abstract

Abstract Selected registered and experimental Bacillus thuringiensis (Bt) formulations and conventional insecticides were evaluated for their efficacy against ECB in field corn plots that had been artificially infested with first-instar larvae. Corn was planted in rows 30 inches wide on 14 May. A randomized complete block design was used, and each treatment was replicated 4 times. Each plot was 4 rows wide and 50 ft long. On 6 Jul, 10 consecutive plants in each of the middle 2 rows of each plot were infested with about 20 ECB larvae that were mixed with corn grits and discharged into the whorl of each plant with a hand-held bazooka applicator. An average of 10 ECB larvae per plant were found in the whorl prior to insecticide applications on 9 Jul. Liquid insecticides were banded over the row with even flat spray tips (Teejet 8004E) delivering 36.5 gpa at 40 psi. Granules were metered over the whorls in a 7-inch band with Noble units. On 14-16 Aug, all plants that had been artificially infested were cut at the base with a corn knife and removed from the field. The number of borer cavities and the total length of cavities per plant were recorded. Numbers of full-grown ECB larvae were also recorded.