In for the kill: novel biosecurity approaches for invasive and medically important mosquito species

Invasive and medically important arthropods continue to spread and establish worldwide whilst adversely impacting ecosystems and public health. As the eradication and population suppression of these invaders and pests can be highly problematic and frequently unsuccessful, prevention of their further spread and establishment is imperative. Currently, however, there remains a lack of efficacious and cost-effective spread prevention techniques; particularly for species with complex life histories that span both aquatic and terrestrial habitats, such as mosquitoes. Here, we examine the use of steam exposure and disinfectant (Virkon® Aquatic) treatments to cause mortality of juvenile life stages of two invasive disease vector mosquitoes, Aedes albopictus and Culex quinquefasciatus. Steam treatments induced total mortality of A. albopictus and C. quinquefasciatus egg stages, following thirty second and five second exposures, respectively. Hatchability of A. albopictus eggs was substantially reduced following ten seconds of steam exposure. Total A. albopictus larval mortality was caused by steam exposures of one second or longer. Conversely, the aquatic disinfectant failed to impede hatchability of A. albopictus or C. quinquefasciatus egg stages. However, disinfection with Virkon® Aquatic caused up to total mortality of mosquito larvae at exposure durations exceeding one minute at 4% concentrations, and five minutes at 1% concentrations. Our results suggest that steam treatments could be implemented as a biosecurity technique to prevent spread and establishment of invasive mosquitoes. Whilst the efficacy of chemical disinfections to cause mortality was not apparent towards mosquito eggs, applications could achieve significant mortality towards larvae in aquatic environments.