ARS | Publication request: Bacillus thuringiensis Cry3Aa toxin increases the susceptibility of Crioceris quatuordecimpunctata to Beauveria bassiana infection

Submitted to: Journal of Invertebrate Pathology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 12, 2011
Publication Date: March 1, 2012
Citation: Gao, Y., Oppert, B.S., Lord, J.C., Liu, C., Lei, Z. 2012. Bacillus thuringiensis Cry3Aa toxin increases the susceptibility of Crioceris quatuordecimpunctata to Beauveria bassiana infection. Journal of Invertebrate Pathology. 109(2): 260-263. http://dx.doi.org/10.1016/j.jip.2011.12.003.

Interpretive Summary: The spotted asparagus beetle is a major pest of asparagus world-wide. There is a need for viable alternatives to chemical insecticides for their control that are compatible with integrated pest management. The most apparent candidate for such an alternative is a commonly used bacterial insecticide, but it is not effective for this beetle. We demonstrated that non-lethal exposure of the beetle to the bacterial insecticide made it more susceptible to a commercial insecticidal fungus. This research will help to provide growers with safe, environmentally friendly alternatives to chemical insecticides.

Technical Abstract: The spotted asparagus beetle, Crioceris quatuordecimpunctata (Coleoptera: Chrysomelidae), is one of the most devastating pests of asparagus in China and elsewhere. In this study, we investigated the interaction of Bacillus thuringiensis (Bt) Cry3Aa toxin and the entomopathogenic fungus Beauveria bassiana pathogenicity against C. quatuordecimpunctata second-instar larvae. When C. quatuordecimpunctata larvae were exposed to a sublethal dose of Cry3Aa toxin, larval mortality associated with B. bassiana was significantly higher than mortality without the toxin. Our results suggest that second-instar C. quatuordecimpunctata larvae exposed to a sublethal dose of Bt Cry3Aa enhances B. bassiana’s biocontrol efficacy. The combined use of both pathogens to improve biocontrol of C. quatuordecimpunctata larvae is discussed.