The Colorado potato beetle, Leptinotarsa decemlineata (Say), is the most destructive insect pest of potato, Solanum tuberosum (L.) in eastern North America. The insect has readily adapted to every insecticide it has encountered. Host plant resistance offers an additional control tactic in an overall integrated pest management strategy, to decrease reliance on insecticides alone. Combining multiple host plant resistance factors into a single cultivar has been suggested as a means to extend the effective life of each individual resistance factor. The objective of this study was to evaluate if the pyramiding of host plant resistance factors provides a better, more durable control. Three different potato lines with natural (leptine glycoalkaloids), engineered (Bacillus thuringiensis-cry3A), and combined host plant resistance factors were evaluated in a no choice detached leaf bioassay. The assays were performed separately on three Colorado potato beetle populations (susceptible, insecticide resistant, and Bt resistant beetles) at each of the four larval instar stages. Ten larvae of same population and initial instar were placed on the foliar tissue for four days; the defoliation of the leaflet and the final instar, weight and mortality of the larvae were recorded. In a no choice situation, the combined host plant resistant (Bt and leptine) line was a more effective control method to deter feeding in Colorado potato beetle larvae.
Species 1: Coleoptera Chrysomelidae Leptinotarsa decemlineata (Colorado potato beetle)
Keywords: Bacillus thuringiensis; Leptine glycoalkaloids
The ESA 2001 Annual Meeting - 2001: An Entomological Odyssey of ESA