Background: The presence of bed bug populations resistant to pyrethroids demands the development of new control tactics, including the use of insecticides with new modes of action. Insecticides that disrupt oxidative phosphorylation in insect mitochondria can be an option. Laboratory assays were used to measure the toxicity of chlorfenapyr to susceptible strains and two strains highly resistant to pyrethroids. The effectiveness of two chlorfenapyr-based formulations was compared, and behavioral responses of bed bugs to dry residues of aerosol sprays were evaluated.
Results: Chlorfenapyr was effective against all bed bug strains, killing them at a similar rate, regardless of their susceptibility status to pyrethroids. Dry residues aged for 4 months were as toxic as fresh dry residues. The aerosol formulation had contact activity and caused faster mortality than a water-based formulation. Bed bugs did not avoid resting on surfaces treated with aerosol.
Conclusion: Chlorfenapyr is an option for controlling pyrethroid-resistant bed bugs. While it does not cause quick knockdown, its long residual activity and no avoidance behavior of bed bugs to dry residues appear to make this insecticide suitable for bed bug control. A faster insecticidal effect is obtained with the aerosol formulation, suggesting greater bioavailability of the toxicant.
Copyright © 2010 Society of Chemical Industry.