Laboratory and field evaluations of Tolfenpyrad on Colorado potato beetle (Leptinotarsa decemlineata Say)

Colorado potato beetle (CPB), Leptinotarsa decemlineata Say, is one of the most important insect pests of potato, Solanum tuberosum L., in North America and Europe. In Virginia, CPB adults and larvae can cause a tremendous amount of defoliation and yield loss in potatoes. In 2010 and 2011, lab toxicity and field efficacy experiments were conducted in Painter, VA to evaluate a novel broad-spectrum insecticide, tolfenpyrad, for the management of CPB. Tolfenpyrad inhibits cellular respiration through inhibition of Complex I of the electron transport chain (IRAC MOA Group 21). Potato leaf dip bioassays conducted on field-collected CPB populations revealed mean LC₅₀ values of 0.012 g AI/Liter for small larvae and ~ 0.5 g AI/Liter for adults. Results from field efficacy trials conducted on potatoes indicated significant control of CPB larvae at rates as low as 0.154 kg ai/ha. Our results indicate that tolfenpyrad is highly efficacious on CPB and could be a useful new mode of action insecticide if registered for use on potatoes in the U.S.