Comparative Susceptibility of Adult and Larval Lesser Mealworms, Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae), Collected from Broiler Houses in Arkansas to Selected Insecticides

Abstract

Loss of insecticide susceptibility was suspected in lesser mealworms, Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae), in broiler chicken facilities in Arkansas due to reports of control failures. Bioassay tests using selected insecticides were conducted on adult and larval beetles collected from broiler chicken production farms having different insecticide application history. The residual and topical application tests showed that previous insecticide use had caused significant differences in the relative susceptibility of lesser mealworms. Topical application bioassay tests indicated that adult beetles had greater susceptibility to the insecticides tested than 8th instars collected from the same farm while in residual tests little difference was generally found in the susceptibility of adults and larvae exposed to the insecticides. Data suggested that the ability to de-toxify DDT and other organochlorine insecticides remained in some beetle populations due to spread of wood-shaving litter containing beetles over pastures among broiler production facilities, particularly involving facilities that have been in broiler production for over 40 y. A program utilizing integrated tactics that will reduce the dependency on insecticides is needed to manage litter beetles in poultry production facilities. The number of poultry production facilities being treated with insecticides to manage the lesser mealworm, Alphitobius diaperinus (Panzer) (Coleoptera: Tenebrionidae), continues to increase in response to the poultry industries attempts to prevent significant economic production losses attributed to the presence of the beetles. Initially, the beetle infestations were reporte da s problematic when the late instars migrated from the wood-shaving or rice hull litter up the facility walls and tunneled into the insulation (Collison 1980) in search of a site in which to molt to the pupal stage followed with the newly emerged adults tunneling out of the insulation. This resulted in extensive economic damage to the insulation (Despins et al. 1987) and resulted in increased heating and cooling costs. Second, starting with the broiler flock initiation with 1- d-old chicks the broilers eat the larval and adult beetles, thus, consuming any