Contact Toxicity and Residual Efficacy of Indoxacarb against the European Earwig (Dermaptera: Forficulidae)

Abstract: Indoxacarb (Arilon 20WG) was evaluated against a nuisance pest, the European earwig (Forficula auricularia), and was found to be an effective contact toxicant with residual activity on substrates commonly encountered in urban environments. Within 16 h of being directly sprayed with indoxacarb, ≥90% of earwigs from two populations were either ataxic, moribund, or dead, and 100% displayed these symptoms of severe intoxication at 1 d. Brief exposure (5 min or 1 h) to dried residues on either a porous (pine wood) or non-porous (ceramic tile) substrate also was sufficient to cause severe intoxication of earwigs within 1 d. In all bioassays, indoxacarb-treated earwigs showed no signs of recovery during the 21-d observation period. In outdoor urban habitats, intoxicated earwigs would be more vulnerable to desiccation, predation, or pathogens leading to higher mortality than in a laboratory setting.