Pest Management Science (2020) 76, 1492-1499

Anders S. Huseth, Damon A. D'Ambrosio, Benjamin T. Yorke, Graham P. Head and George G. Kennedy (2020)
Novel mechanism of thrips suppression by Cry51Aa2.834_16 Bt toxin expressed in cotton
Pest Management Science 76 (4), 1492-1499
Abstract:
BACKGROUND
Genetically engineered (GE) crops that express insecticidal traits have improved the sustainability of insect pest management worldwide, but many important pest orders are not controlled by commercially available toxins. Development of the first transgenic thysanopteran- and hemipteran-active Bacillus thuringiensis (Bt) Cry51Aa2.834_16 toxin expressed in MON 88702 cotton will significantly expand the diversity of pests controlled in the crop. Here, we examined MON 88702 cotton activity against two thrips species within the same genera, Frankliniella fusca and Frankliniella occidentalis. We used a multi-component cotton tissue assay approach to understand effects on adult longevity, fecundity, and larval development.
RESULTS
We found that in no-choice assays, cotton plants expressing MON 88702 suppress oviposition, when compared to a non-Bt cotton. MON 88702 did not kill a large proportion of F. fusca larvae or adults but killed most F. occidentalis larvae. Time series experiments with F. occidentalis larvae documented significant developmental lags for MON 88702 exposed individuals. We also found that female thrips preferred to oviposit on non-Bt cotton when provided a choice.
CONCLUSION
Together these results describe the activity of MON 88702 against thrips. They document clear differences in toxin performance between different thrips species and throughout the insects' life cycle. Most importantly, we show that MON 88702 was associated with reduced oviposition via behavioral avoidance to the toxin. This is a novel mechanism of action for pest control for a Bt crop plant. Together, these results provide a basis to describe the mechanism of population control for MON 88702 cotton.
(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): Anders S. Huseth, Graham Head, George G. Kennedy

Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
evaluation - screening - selection

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Frankliniella occidentalis	Cotton (Gossypium)
	Frankliniella fusca	Cotton (Gossypium)
Bacillus thuringiensis Cry51A-toxin (entomopathogen)	Frankliniella occidentalis	Cotton (Gossypium)
Bacillus thuringiensis Cry51A-toxin (entomopathogen)	Frankliniella fusca	Cotton (Gossypium)