Quantifying the contribution of seed blended refugia in field corn to helicoverpa zea (lepidoptera : noctuidae) populations

Authors: TOWELS, T. B. - Mississippi State University; BUNTIN, G. D. - University Of Georgia; CATCHOT, A. L. - Mississippi State University; GORE, J. - Mississippi State University; COOK, D.R. - Mississippi State University; CAPRIO, M.A - Mississippi State University; DAVES, C - Bayer Cropscience

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/20/2021
Publication Date: 5/24/2021
Citation: Towels, T., Buntin, G., Catchot, A., Gore, J., Cook, D., Caprio, M., Daves, C. 2021. Quantifying the contribution of seed blended refugia in field corn to Helicoverpa zea (Lepidoptera : Noctuidae) populations. Journal of Economic Entomology. 114:1771–1778. https://doi.org/10.1093/jee/toab097.
DOI: https://doi.org/10.1093/jee/toab097

Interpretive Summary: Bollworm is a pest of cotton that also feeds on field corn. This pest is commonly controlled through the use of foliar-applied insecticides or transgenic crops expressing Bacillus thuringiensis (Bt) genes. Refuge systems have been implemented to minimize the development of resistance to Bt proteins produced by transgenic crops. Historically, structured refuge compliance among growers has been low, leading to the commercialization of seed blended refugia. To test the viability of seed blended refugia in southern U.S. field corn, field studies were conducted in Mississippi and Georgia during 2016, 2017, and 2018 growing seasons. To quantify adult H. zea emergence from structured (non-Bt corn) and seed blended refuge options, emergence traps were utilized. Kernel damage among seed blended refuge and structured refuge corn ears were recorded and compared. The timing of moth emergence was recorded. When compared to a structured refuge, H. zea adult moth emergence from seed blended refugia did not significantly differ. Kernel damage of non-Bt plants in the seed blended treatments was not significantly different than non-Bt plants in the structured refuge treatments. Moth emergence timing was not significantly delayed between the structured refuge and seed blended refuge treatments. Results of this study suggest that a seed blended refuge may provide an effective insecticide resistance management alternative for H. zea in areas where structured refuge compliance is low.

Technical Abstract: Helicoverpa zea (Boddie), a pest of cotton that also occurs in field corn, is commonly controlled through the use of foliar-applied insecticides or transgenic crops expressing Bacillus thuringiensis (Berliner) (Bt) genes. To minimize the risk of Bt resistance in pest populations, refuge systems have been implemented for sustainable agroecosystem management. Historically, structured refuge compliance among growers has been low, leading to the commercialization of seed blended refugia. To test the viability of seed blended refugia in southern U.S. field corn, field studies were conducted in Mississippi and Georgia during 2016, 2017, and 2018 growing seasons. To quantify adult H. zea emergence from structured (non-Bt corn) and seed blended refuge options, emergence traps were utilized. Kernel damage among seed blended refuge and structured refuge corn ears were recorded and compared. The timing of moth emergence was recorded. When compared to a structured refuge, H. zea adult moth emergence from seed blended refugia did not significantly differ. Kernel damage of non-Bt plants in the seed blended treatments was not significantly different than non-Bt plants in the structured refuge treatments. Moth emergence timing was not significantly delayed between the structured refuge and seed blended refuge treatments. Results of this study suggest that a seed blended refuge may provide an effective insecticide resistance management alternative for H. zea in areas where structured refuge compliance is low.