Effectiveness of Bt Newleaf® Potato to ControlLeptinotarsa Decemlineata(Say) (Coleoptera: Chrysomelidae) in Bulgaria

Laboratory and field studies were conducted in 2000 and 2002 in Bulgaria to evaluate the efficacy of transgenic Bt potato (Newleaf®) against the Colorado potato beetle (CPB) Leptinotarsa decemlineata. Younger larvae of CPB were more susceptible to Bt potato leaves than older and died 100% during one day. The least defoliation of potato plants by CPB and the lowest number of overwentering adults of this pest were observed in Bt plots. Results from two year trials demonstrated that Bt potato plants were highly effective and provided better CPB control than insecticides Vaztak® and Regent®.