Integration of Insecticides and Biological Control Tactics for Sweet Corn 2000
Project Leaders: F. R. Musser and A. M. Shelton
Sweet corn is attacked by a variety of insect pests that can cause severe losses to the producer. Current control practices are largely limited to the application of broad-spectrum insecticides that can have a substantial and deleterious impact on the natural enemy complex. When not killed by broad-spectrum insecticides, natural enemies have been shown to provide partial control of sweet corn pests. The major natural enemies in New York sweet corn are two species of lady beetles and Orius insidiosus. New products that specifically target pests, while being relatively benign to other insects, could enable growers to have the benefits of natural enemies and still use insecticides as needed. In field trials we found that Avaunt and SpinTor are both less toxic to some natural enemies than the pyrethroid Warrior. Avaunt, however, was highly toxic to lady beetles, and SpinTor was slightly toxic to O. insidiosus at labeled field rates. Both of these new products were able to provide control of the primary pests equal to Warrior. Transgenic Bt sweet corn varieties provided excellent control of pests and showed no toxicity to the natural enemies monitored, while Dipel, a Bt foliar spray formulation, provided no significant pest control and was slightly toxic to lady beetles. The choice of insecticide material had a major impact on survival of both the pests and natural enemies in sweet corn, but the rate and frequency of application had only minor impacts. Thirteen commercial varieties were screened for resistance to pests and attractiveness to natural enemies. Significant differences occurred between varieties for populations of European corn borer, lady beetles, O. insidiosus, and aphids, indicating that there is potential to select varieties for host resistance and increased pest control by natural enemies.