Pest Management Science (2005) 61, 1186-1192
Hany M. Hussein, Oxana Habustová and Frantisek Sehnal (2005)
Beetle-specific Bacillus thuringiensis Cry3Aa toxin reduces larval growth and curbs reproduction in Spodoptera littoralis (Boisd.)
Pest Management Science 61 (12), 1186-1192
Abstract: Application of Bacillus thuringiensis tenebrionis (Bt) and expression of the Bt protein Cry3Aa in genetically modified crops are used for targeted control of the Colorado potato beetle Leptinotarsa decemlineata (Say). The Cry3A proteins are selectively toxic for the beetles but the present study describes effects of Cry3Aa on the Egyptian armyworm, Spodoptera littoralis (Boisduval). Cry3Aa expressed in potatoes or added to an agar-base wheat-germ diet reduced the growth of S. littoralis caterpillars and the fertility of adults. The effect of 1.4 mg kg-1 Cry3Aa in potato leaves was comparable with that of 3.3 mg kg-1 in the diet. This difference in activity was correlated with better digestibility and higher conversion efficiency of the diet that also supported higher reproduction rate: S. littoralis grown on the potatoes reached a similar size to those on the diet but laid only 702 instead of 1077 eggs per female. Cry3Aa consumption reduced body growth as a consequence of lower food intake without significantly affecting food digestibility and the conversion efficiency of nutrients. The 11% and 5% body weight reductions caused by 1.4 mg kg-1 Cry3Aa in potatoes and 3.3 mg kg-1 in the diet, respectively, were associated with 74% and 65% reduction in the number of progeny; S littoralis grown on a diet with 9.1 mg kg-1 Cry3Aa were 10% smaller and produced no viable progeny. These data suggest that the curtailment of reproduction was not caused by a general shortage of nutrient reserves but by a more direct Cry3Aa effect on the reproduction process.
(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): Frantisek Sehnal
Research topic(s) for pests/diseases/weeds:
biocontrol - natural enemies
Research topic(s) for beneficials or antagonists:
general biology - morphology - evolution
Pest and/or beneficial records:
| Beneficial | Pest/Disease/Weed | Crop/Product | Country | Quarant.
|
|---|---|---|---|---|
| Spodoptera littoralis | ||||
| Bacillus thuringiensis Cry3A-toxin (entomopathogen) | Spodoptera littoralis |
