Limited efficacy of insecticide dusts through contact and entomophagy of treated prey on Arizona bark scorpions, Centruroides sculpturatus

Centruroides sculpturatus Ewing stands apart from other Southwestern urban pest arthropods as one of the few medically relevant arthropods in the United States. Colloquially known as the Arizona bark scorpion, the sting of this scorpion can result in symptoms that range from extreme regional pain to vital organ failure. Control of C. sculpturatus almost exclusively relies on insecticide sprays, which are not always effective. Insecticide dusts may provide better control for scorpions because the dusts can penetrate cracks and crevices where scorpions and their prey commonly reside as well as remain efficacious for longer periods. The effectiveness of various insecticide dust formulations transferred via Turkestan cockroach (Periplaneta lateralis Walker) nymphs was evaluated in this study. Scorpions were randomly assigned to an arena and given a single cockroach nymph that had been pretreated with one of seven insecticide dusts or an untreated control. Although many of the treated nymphs were consumed, scorpion mortality was low. Surprisingly, scorpions presented Tri-Die and Tempo 1% treated prey were reluctant to consume the prey item but contact with the corpse for several days was sufficient to elicit a toxic effect. Scorpions presented nymphs treated with Advion® MicroFlow consumed almost all the prey items and experienced minimal mortality. This study shows that contact with insecticide dust-treated prey can elicit a lethal effect however formulation of the dust may play a role in causing mortality via entomophagy or contact.