Longitudinal trials illustrate interactive effects between declining Bt efficacy against Helicoverpa zea (Lepidoptera: Noctuidae) and planting dates of corn.

Autor:	Reay-Jones FPF; Department of Plant and Environmental Sciences, Pee Dee Research and Education Center, Clemson University, Florence, SC 29506-9727, USA., Buntin GD; Department of Entomology, University of Georgia, Griffin, GA 30223, USA., Reisig DD; Department of Entomology and Plant Pathology, North Carolina State University, The Vernon G. James Research and Extension Center, Plymouth, NC 27962, USA., Bridges WC Jr; Department of Mathematical Sciences, Clemson University, Clemson, SC, 29634, USA.
Jazyk:	angličtina
Zdroj:	Journal of economic entomology [J Econ Entomol] 2024 Oct 14; Vol. 117 (5), pp. 1901-1912.
DOI:	10.1093/jee/toae160
Abstrakt:	Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae) has evolved resistance to insecticidal toxins from Bacillus thuringiensis (Bt) Berliner (Bacillales: Bacillaceae) expressed in genetically engineered corn, Zea mays L. This study provides an overview of field trials from Georgia, North Carolina, and South Carolina evaluating Bt and non-Bt corn hybrids from 2009 to 2022 to show changes in susceptibility in H. zea to Bt corn. The reduction in kernel injury relative to a non-Bt hybrid averaged across planting dates generally declined over time for Cry1A.105 + Cry2Ab2 corn. In addition, there was a significant interaction with planting date used as a covariate. The reduction in kernel injury remained above 80% and did not vary with planting date from 2009 to 2014, whereas a significant decline with planting date was found in this reduction from 2015 to 2022. For Cry1Ab + Cry1F corn, the reduction in kernel injury relative to a non-Bt hybrid averaged across planting dates did not vary among years. The reduction in kernel injury significantly declined with planting date from 2012 to 2022. Kernel injury as a proxy for H. zea pressure was greater in late-planted trials in non-Bt corn hybrids. Our study showed that Bt hybrids expressing Cry1A.105 + Cry2Ab2 are now less effective in later planted trials in reducing H. zea injury; however, this was not the case during the earlier years of adoption of corn expressing these 2 toxins when resistance alleles were likely less frequent in H. zea populations. The implications for management of H. zea and for insect resistance management are discussed. (© The Author(s) 2024. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)
Databáze:	MEDLINE
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