Efficacy of transfluthrin varies by species and placement in a warm temperate Mediterranean environment

Authors: POWELL, R T - US Department Of Agriculture (USDA); MIAOULIS, M - US Department Of Agriculture (USDA); TSAFRAKIDOU, PANAGIOTA - US Department Of Agriculture (USDA); GIANTSIS, I - US Department Of Agriculture (USDA); Linthicum, Kenneth - Ken; Kline, Daniel - Dan; CHASKOPOULOU, A - US Department Of Agriculture (USDA); Gibson, Seth

Submitted to: Journal of the American Mosquito Control Association
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/19/2024
Publication Date: N/A
Citation: N/A

Interpretive Summary: Spatial repellents are a new kind of chemical pest control technology that in theory should repel biting insects such as mosquitoes from people in small areas such as a tent or while sitting on a chair outdoors. The novel feature of these chemicals is that they will not kill the insects if they fly away from the protected area, which, in contrast to pesticide treatments designed to kill insects, should reduce the likelihood that the insect populations will adapt to the chemical and fly through it to bite someone. Military personnel are particularly vulnerable to mosquito bites in the field which could reduce operational capabilities. We designed an experiment in an outdoor area in Greece with natural populations of mosquitoes that can transmit diseases such as West Nile virus and sand flies that can transmit devastating skin and organ diseases to humans to determine whether a spatial repellent could protect small tents as well as small outdoor areas lacking shelter from these insects. We found that the spatial repellent was not effective against mosquitoes but could keep sand flies away out in the open. However we also found that using the spatial repellent in the tent caused the accumulation of mosquitoes in the tents and was not effective at reducing sand flies in the tent. We discuss how future development of spatial repellents should cautiously integrate this technology into everyday use.

Technical Abstract: Spatial repellents such as transfluthrin are poised to revolutionize integrated vector management with products that may protect personnel in limited areas from incursion of vector or nuisance Diptera such as mosquitoes and sand flies while not triggering the evolution of resistance. However, investigations with spatial repellents have revealed a spectrum of efficacy depending on factors such as target species or the environment. We investigated the efficacy of resin diffusers impregnated with transfluthrin in protecting two simulated military field scenarios – a partially opened tent and an open bivouac lacking a shelter – from natural populations of disease vector Culex species mosquitoes and Phlebotomus ¬species sand flies. We found that transfluthrin sufficiently protected the open air location from sand flies but not mosquitoes, whereas sand fly collections were not affected and mosquito collections significantly increased inside treated tents. We discuss that spatial repellents should be incorporated into integrated vector management with caution.