Journal of Economic Entomology (2008) 101, 933-943

Fengyi Liu, Zhiping Xu, Juhua Chang, Jin Chen, Fengxia Meng, Yu Cheng Zhu and Jinliang Shen (2008)
Resistance allele frequency to Bt cotton in field populations of Helicoverpa armigera (Lepidoptera: Noctuidae) in China
Journal of Economic Entomology 101 (3), 933-943
Abstract: Resistance evolution in target insects to Bacillus thurningiensis (Bt) cotton, Gossypium hirsutum L., is a main threat to Bt cotton technology. An increasing trend of population density of Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae) has been observed since 2001 in Qiuxian County (Hebei, China), where Bt cotton has been planted dominantly since 1998. This region was selected in 2006 and 2007 for estimating frequency of gene alleles conferring resistance to Bt cotton by screening the F₁ progeny from single-pair cross between field-collected male and laboratory female of the Bt-resistant strain of H. armigera (F₁ screen). F₁ offspring from each single-pair line were screened for resistance alleles based on larval growth, development, and survival on Bt cotton leaves for 5 d. Two-year results indicated that ~ 20% of field-collected males carried resistance alleles. The conservative estimate of the resistance allele frequency was 0.094 (95% CI, 0.044-0.145) for 2006 and 0.107 (95% CI, 0.055-0.159) for 2007. This is the first report of resistance allele frequency increase to such a high level in the field in China. Long-term adoption of Bt sprays, dominant planting of single-toxin-producing Bt cotton, and lack of conventional cotton refuge system might accelerate the resistance evolution in the region.
(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): Jin Liang Shen

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 (NE)
Bacillus thuringiensis genes in crops (entomopathogen)	Helicoverpa armigera	Cotton (Gossypium)	China (NE)