Pest Management Science (2004) 60, 167-172

Fengxia Meng, Jinliang Shen, Weijun Zhou and Hongmei Cen (2004)
Long-term selection for resistance to transgenic cotton expressing Bacillus thuringiensis toxin in Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae)
Pest Management Science 60 (2), 167-172
Abstract: Selection experiments for resistance to transgenic Bt cotton expressing Cry1Ac toxin in Helicoverpa armigera (Hübner) were conducted using a leaf-feeding method with 42 selection episodes over 45 generations. The cotton bollworm developed resistance to transgenic Bt cotton after 12 generations (F₁₂) of selection. The survival rate of F₁₂ neonates feeding on leaves of seedling stage for 4 days and boll-opening stage for 5 days of R₁₉ line were ca 34 and 72%, respectively, compared with ca 0 and 40% for a non-selected sister strain (NYCS), but lower than or similar to that of F₁₂ feeding on leaves of non-Bt cotton, Sumian 12 (ca 87 or 76%). Resistance to B thuringiensis HD-1 Dipel in neonates (F₁₂) was ca 6-fold. After 42 generations of selection, the strain developed a very high level of resistance to Cry1Ac protoxin, 210 g kg^-1 MVPII wettable powder and 200 g litre^-1 MVPII liquid formulation, the resistance ratios being 1680-, 1780- and ca 1200-fold, respectively, compared with a laboratory susceptible strain (HZS). When compared with the non-selected NYCS, the resistance ratios to the above toxins were ca 540-, 580- and 510-fold, respectively, but to Dipel only ca 16-fold. The results indicated that it is very important to develop and implement effective resistance-management strategies and to detect early resistance to Bt cotton in field populations.
(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)
Bacillus thuringiensis genes in crops (entomopathogen)	Helicoverpa armigera	Cotton (Gossypium)
Bacillus thuringiensis Cry1A-toxin (entomopathogen)	Helicoverpa armigera	Cotton (Gossypium)