Entomologia Experimentalis et Applicata (2019) 167, 868-879

Tuyet Thi Anh Luong, Bronwen W. Cribb, Sharon J. Downes, Lynda E. Perkins and Myron P. Zalucki (2019)
Stay or move: how Bt-susceptible Helicoverpa armigera neonates behave on Bt cotton plants
Entomologia Experimentalis et Applicata 167 (10), 868-879
Abstract: Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) larvae occasionally have been reported to survive at management threshold levels in fields of Bollgard II^® cotton, Gossypium hirsutum L. (Malvaceae). The pattern and degree of larval survival is not easily predicted but depends on the ability of first instars to establish on host plants. Experiments were conducted with Bacillus thuringiensis Berliner (Bt)-susceptible and Bt-resistant larvae of H. armigera to understand how physiologically Bt-susceptible H. armigera survive on Bt cotton plants, and examine how their first meal influences survival rates. In assays using cotton plant parts, both strains of larvae displayed similar tendencies to drop-off specific plant parts of Bt and non-Bt cotton. However, significantly more Bt-susceptible larvae dropped off young leaves, mature leaves, and squares of Bt cotton compared to non-Bt cotton plants. Egg cannibalism significantly improved the survival of Bt-susceptible H. armigera larvae on Bt cotton plants. Larvae were more likely to eat live aged eggs, than newly laid or dead eggs. Survival significantly improved when larvae cannibalized eggs before feeding on Bt leaves. The behavior of Bt-susceptible larvae with respect to drop-off and egg cannibalism may help enhance their survival on Bt cotton plants.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Tuyet T.A. Luong, Sharon Downes, Lynda E. Perkins, Myron P. Zalucki

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
resistance/tolerance/defence of host
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Helicoverpa armigera	Cotton (Gossypium)
Bacillus thuringiensis genes in crops (entomopathogen)	Helicoverpa armigera	Cotton (Gossypium)