Efficacy of contact insecticides for the control of the lesser mealworm, Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae)

Abstract

The lesser mealworm, Alphitobius diaperinus is a common pest of poultry farming facilities, the presence of which harbors diseases and economic loss, but it also occurs in different types of storage and processing facilities, such as feed mills. In this study, we evaluated the efficacy of three contact insecticides, alpha cypermethrin, spinosad, and pirimiphos methyl, against adults and larvae of A. diaperinus in a series of two bioassays. In the first series of bioassays, mortality rates were determined after 1, 3, 7 and 14 days of exposure on concrete dishes treated with the above insecticides. The results show that all three insecticides were effective for the control of this species, since after 14 days of exposure mortality exceeded 90% for both adults and larvae. Spinosad had a definite advantage over the other two insecticides, providing complete (100%) insect mortality after 14 days of exposure. In the second series of bioassays, the presence of food was evaluated to determine the effects of immediate and delayed mortality. We found that the presence of food in the concrete dishes decreased the levels of delayed mortality of the exposed individuals. All three insecticides showed an increased level of delayed mortality, either with or without food, but mortality did not reach 100% for any of the combinations tested. These results present a valid series of data for creating a standardized means of control against this pest that has beset poultry facilities for years.