Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: January 2, 1998
Publication Date: March 10, 1998
Citation: Tillman, P.G., Mulrooney, J.E., Mitchell, W. 1998. Susceptibility of selected beneficial insects to DPX-MPO62. Proceedings of the Beltwide Cotton Conference. p. 1112-1113. Interpretive Summary: The tobacco budworm and the corn earworm are important leaf feeding insect pests of cotton, and worm infestations can destroy a field of cotton. I am actively looking for methods to minimize damage by these insects while reducing the use of insecticides. The parasitic wasps, Cardiochiles nigriceps, Microplitis croceipes, and Cotesia marginiventris, and the predators Coccinella septempunctata, the C-7 lady beetle, and Geocoris punctipes, the big-eyed bug, are predominant natural enemies of these pests in the south. We are determining methods to conserve these natural enemies for control of these pests. The purpose of this study was to determine the effect of Steward, a new insecticide of Du Pont Agricultural Products for worm control, on survival of these natural enemies. In summary, residues of Steward had no significant effect on survival of the beneficial insects as tested. Generally, except for the wasp C. marginiventris, the lower rates of Steward were not toxic to the beneficial insects when the insecticides were applied directly to the insects. Selective use of the insecticides which resulted in higher survival could conserve these native biological control agents increasing their effectiveness.
Technical Abstract: Effects of DPX-MP062 (Steward in cotton, Du Pont Agricultural Products, Wilmington, DE) on survival of five natural enemies, Cardiochiles nigriceps, Coccinella septempunctata, Geocoris punctipes, Microplitis croceipes, and Cotesia marginiventris were determined. For C. nigriceps, C. septempunctata, and G. punctipes, treatment by Steward at the lower rates (0.045-0.065 lb ai/a) resulted in high to moderately high survival when sprayed directly onto the insects. The highest rate of Steward was very toxic to C. marginiventris and G. punctipes. Except for C. marginiventris, the lower rates (0.045-0.065 lb ai/a) of Steward were much less toxic than Karate. Survival of C. marginiventris and G. punctipes was high after 24 h of exposure to residues of Steward on cotton leaves. Exposure to Steward residues on cotton leaves at 0 and 2 hours after treatment in the field did not effect survival of C. nigriceps, C. septempunctata, G. punctipes, or M. croceipes.