Fall armyworm oviposition on cotton plants expressing widestrike™, Bollgard® , and Bollgard II® Cry proteins

Document Type

Article

Publication Date

9-1-2012

Abstract

Cotton, Gossypium hirsutum (L.), plants expressing insecticidal crystal (Cry) proteins from Bacillus thuringiensis Berliner (Bt) constitute the majority of cotton acreage planted across the southern region of the United States. Fall armyworm, Spodoptera frugiperda (J. E. Smith), can be a significant cotton pest in some years, but this species has not been a primary target of Bt cotton technologies. The objective of this study was to characterize fall armyworm oviposition sites on cotton plants expressing Bt proteins. Fall armyworm adults were released into isolation cages containing cotton plants expressing either single (Bollgard®, Cry1Ac) or pyramided proteins (Bollgard II®, Cry1Ac:Cry2Ab; WideStrike™, Cry1Ac:Cry1F) or a conventional non-Bt cotton line. Following an oviposition period of two-three days, cotton plants were destructively sampled to locate egg masses. The distribution of egg masses on Bt cotton plants was not significantly different from that on non-Bt plants. Most egg masses were recorded on leaves, predominately on the abaxial surface, regardless of cotton line. Significantly more egg masses (>68%) were deposited on leaves near or emerging directly from the main stem (sympodial branch nodes 02) than on leaves emerging from branch nodes farther from the main stem. Fall armyworm oviposition was not influenced by Bt proteins and sampling protocols for eggs and early instars should be similar in fields of Bt and non-Bt cotton plants.

Publication Source (Journal or Book title)

Southwestern Entomologist

First Page

295

Last Page

303

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