Transfluthrin spatial repellent on US military materials reduces Culex tarsalis incursion in a desert environment

Authors: Gibson, Seth; Linthicum, Kenneth - Ken; Kline, Daniel - Dan; Aldridge, Robert; Golden, Frances; WITTIE, JEREMY - Coachella Valley Mosquito And Vector Control District; HENKE, JENNIFER - Coachella Valley Mosquito And Vector Control District; HUNG, KIM - Coachella Valley Mosquito And Vector Control District; GUTIERREZ, ARTURO - Coachella Valley Mosquito And Vector Control District; SNELLING, MELISSA - Coachella Valley Mosquito And Vector Control District; LORA, CIRILO - University Of Florida

Submitted to: Journal of the American Mosquito Control Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/10/2020
Publication Date: 3/1/2020
Citation: Britch, S.C., Linthicum, K., Kline, D.L., Aldridge, R.L., Golden, F.V., Wittie, J., Henke, J., Hung, K., Gutierrez, A., Snelling, M., Lora, C. 2020. Transfluthrin spatial repellent on US military materials reduces Culex tarsalis incursion in a desert environment. Journal of the American Mosquito Control Association. 36(1):37-42. https://doi.org/10.2987/19-6894.1.
DOI: https://doi.org/10.2987/19-6894.1

Interpretive Summary: Treatment of perimeters of US military materials such as camouflage netting with standard residual pesticides may protect health and morale of US military personnel in the field by reducing incursion of disease vector or nuisance biting insects such as mosquitoes or sand flies into protected areas. However, standard residual pesticides rely on target insects resting on treated surfaces to accumulate lethal or sub-lethal doses; those that do not contact the treatment may still host seek. Furthermore, heavy mortality from residuals translates to evolution of resistance and subsequent loss of efficacy of this technique. Emerging availability of diverse spatial repellents and toxicants such as transfluthrin leveraged as residuals on military materials offers an alternative to standard residual formulations less likely to induce resistance. Residual applications of transfluthrin could form a volatile repellent plume allowing target insects the chance to escape, only inducing mortality if insects linger for example after becoming trapped in a tent, and not requiring contact with treated surfaces. In this study we investigated the capability of transfluthrin on two types of US military materials in a variety of realistic scenarios to reduce natural populations of disease vector and nuisance mosquitoes in a cool arid desert field environment. We found that transfluthrin could substantially reduce target insect incursion into protected areas, and in two scenarios reduce collections outside protected areas, for up to 16 days showing that this compound could be an effective element in the US Department of Defense pest management system. We also observed variation in transfluthrin efficacy across species which has implications for designing integrated vector management using a variety of measures that harmonize in a system to reduce incursion across the community of biting insects that may be present.

Technical Abstract: Treatment of perimeters of US military materials such as camouflage netting with standard residual pesticides may protect health and morale of US military personnel in the field by reducing incursion of disease vector or nuisance biting insects such as mosquitoes or sand flies into protected areas. However, standard residual pesticides rely on target insects resting on treated surfaces to accumulate lethal or sub-lethal doses; those that do not contact the treatment may still host seek. Furthermore, heavy mortality from residuals translates to evolution of resistance and subsequent loss of efficacy of this technique. Emerging availability of diverse spatial repellents and toxicants such as transfluthrin leveraged as residuals on military materials offers an alternative to standard residual formulations less likely to induce resistance. Residual applications of transfluthrin could form a volatile repellent plume allowing target insects the chance to escape, only inducing mortality if insects linger for example after becoming trapped in a tent, and not requiring contact with treated surfaces. In this study we investigated the capability of transfluthrin on two types of US military materials in a variety of realistic scenarios to reduce natural populations of disease vector and nuisance mosquitoes in a cool arid desert field environment. We found that transfluthrin could substantially reduce target insect incursion into protected areas, and in two scenarios reduce collections outside protected areas, for up to 16 days showing that this compound could be an effective element in the US Department of Defense pest management system. We also observed variation in transfluthrin efficacy across species which has implications for designing integrated vector management using a variety of measures that harmonize in a system to reduce incursion across the community of biting insects that may be present.