Susceptibility of lesser mealworm (Coleoptera: Tenebrionidae) adults and larvae exposed to two commercial insecticides on unpainted plywood panels

BACKGROUND: The susceptibilities of adult and larval lesser mealworms, Alphitobius diaperinus (Panzer), to two commercially formulated insecticides, cyfluthrin and tetrachlorvinphos, were examined through exposure on treated plywood panels. Lesser mealworms were collected from four caged-layer poultry farms, three in New York and one in Maine. An additional strain was obtained from an infestation occurring in a cricket colony.RESULTS: In all poultry farm derived strains, a portion of the population (1.8-16.2%) survived cyfluthrin exposure. The Maine and cricket colony strains were tolerant of tetrachlorvinphos exposure as both larvae and adults, with 55-74% mortality, whereas nearly 100% mortality was observed with New York strains. The cricket colony adult beetles were highly susceptible to cyfluthrin, with 100% mortality following exposure, but larvae were considerably less susceptible (87.7%). Pesticide use histories for the poultry farms and their impact on the results are discussed.CONCLUSION: The results document that tetrachlorvinphos, an active ingredient with a long use history, may be losing its effectiveness against lesser mealworms in some poultry operations; however, it is still effective in many others.