Rapid pesticide resistance bioassays for three major urban insects in Taiwan

Abstract Background Taiwan’s warm and humid climate and dense population provide a suitable environment for the breeding of pests. The three major urban insects in Taiwan are house flies, cockroaches, and mosquitoes. In cases where a disease outbreak or high pest density necessitates chemical control, selecting the most effective pesticide is crucial. The resistance of pests to the selected environmental pesticide must be rapidly assessed to achieve effective chemical control and reduce environmental pollution.Methods In this study, we evaluated the resistance of various pests, namely, house flies (Musca domestica L.), cockroaches (Blattella germanica L. and Periplaneta americana), and mosquitoes (Aedes aegypti and Aedes albopictus), against 10 commonly used insecticides. Rapid pesticide resistance bioassays were performed using discriminating doses or concentrations of the active ingredients of insecticides.Results Five field strains of M. domestica (L) were resistant to all 10 commonly used insecticides and exhibited cross-resistance and multiple resistance to four types of pyrethrins and three types of organophosphates, propoxur, fipronil, and imidacloprid. None of the five field strains of P. americana were resistant to any of the tested insecticides, and only one strain of B. germanica (L.) was resistant to permethrin. One strain of A. albopictus was resistant to pirimiphos-methyl, whereas five strains of A. aegypti exhibited multiple resistance to pyrethrins, organophosphates, and other insecticides.Conclusions In the event of a disease outbreak or high pest density, rapid pesticide resistance bioassays may be performed using discriminating doses or concentrations to achieve precise and effective chemical control, reduce environmental pollution, and increase control efficacy.