Physiology, Biochemistry, and Toxicology
Section Symposium
Thais Rodrigues
Head of Discovery Biology
GreenLight Biosciences
Durham, North Carolina
Andrei Alyokhin
University of Maine
Orono, Maine
Brian Manley
GreenLight Biosciences
Wake Forest, North Carolina
Kenneth Narva
Head of Entomology, Research Fellow
GreenLight Biosciences
Research Triangle Park, North Carolina
Thais B. Rodrigues, Sambit K. Mishra, Rich Tuttle, David Garby, Ethann R. Barnes, Andrei Alyokhin, Kokulapalan Wimalanathan, Krishnakumar Sridharan, Nicholas J. Skizim, Yu-wen Tang, Brian Manley, Ronald Flannagan, Carole Cobb, Lorenzo Aulisa, Kenneth E. Narva
Colorado potato beetle (CPB, Leptinotarsa decemlineata) is a major pest of potato and other solanaceous vegetables in the Northern Hemisphere. The insect feeds on leaves and can completely defoliate crops. Because of the repeated use of single insecticide classes without rotating active ingredients, many chemicals are no longer effective in controlling CPB. Ledprona is a sprayable double-stranded RNA (dsRNA) biopesticide with a new mode of action that triggers the RNA interference (RNAi) pathway. Laboratory assays with second instar larvae fed Ledprona showed a dose-response where 25 X 10-6 g/L of dsPSMB5 caused 90% mortality after six days of initial exposure. We also showed that exposure to Ledprona for 6hr caused larval mortality and decreased target mRNA expression. Decrease of PSMB5 protein levels were observed after 48hr of larval exposure to Ledprona. Both PSMB5 mRNA and protein levels did not recover over time. Ledprona efficacy was demonstrated in a whole plant greenhouse trial and performed similarly to spinosad. Ledprona, currently pending registration at EPA, represents a new biopesticide class integrated pest management (IPM) and insecticide resistance management programs directed against CPB.