Environmental Entomology (2010) 39, 1698-1704

Guoping Li, Hongqiang Feng, Yulin Gao, Kris A.G. Wyckhuys and Kongming Wu (2010)
Frequency of Bt resistance alleles in Helicoverpa armigera in the Xinjiang cotton-planting region of China
Environmental Entomology 39 (5), 1698-1704
Abstract: Helicoverpa armigera Hübner (Lepidoptera: Noctuidae) is a key insect pest of cotton in Xinjiang cotton-planting region of northwest China. In this region, cotton is grown on average ~ 1.65 million ha (1.53 ~ 1.80 million ha) annually in largely monoculture agricultural landscapes, similarly to cropping systems in the United States or Australia. Under such cropping regimes, naturally occurring refuges (with non-Bt crops) may be insufficient to prevent H. armigera resistance development to Bt toxins. Therefore, we assessed frequency of alleles conferring resistance to Cry1Ac toxin of F₁ and F₂ offspring of H. armigera isofemale lines from two distinct localities in the region during 2005-2009. More specifically, a total of 224 isofemale lines was collected from Korla County (~70% Bt cotton adoption) and 402 lines from Shache County (~5% Bt cotton planting). Subsequent offspring was screened on Cry1Ac artificial diet. From 2005 to 2009, resistance gene frequency in Korla fluctuated between 0.0000 and 0.0040, while being 0.0000-0.0008 in individuals collected from Shache, and there were no significant increases in both counties from 2005 to 2009. Relative average development rates (RADRs) of larvae in F₁ tests showed significant increases from Korla, but not in Shache. RADR of F₁ larvae is significantly correlated with RADR of F₂ offspring, indicating genetic variation in response to toxin in field H. armigera population. Although the occurrence of Cry1Ac resistance alleles was low in Xinjiang cotton-planting region of China, particular attention should be given to H. armigera resistance development in Korla County.
(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): Kong Ming Wu, Yulin Gao, Kris A.G. Wyckhuys

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

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Helicoverpa armigera	Cotton (Gossypium)	China (NW)
Bacillus thuringiensis genes in crops (entomopathogen)	Helicoverpa armigera	Cotton (Gossypium)	China (NW)
Bacillus thuringiensis Cry1A-toxin (entomopathogen)	Helicoverpa armigera	Cotton (Gossypium)	China (NW)