Prallethrin-induced excitation increases contact between sprayed ultralow volume droplets and flying mosquitoes (Diptera: Culicidae) in a wind tunnel.

Female Culex quinquefasciatus Say (Diptera: Culicidae) mosquitoes were exposed to sublethal amounts of prallethrin, sumithrin, and piperonyl butoxide applied as ultralow volume (ULV) droplets in a wind tunnel. Mosquitoes were video recorded before, during, and after treatment, and the number and size of droplets on their bodies were later determined using a compound microscope. A positive correlation was found between mosquitoes that spent more time flying during the time of spraying and number of droplets on their bodies. Excitation, in the form of increased speed and duration of flight, was immediate in mosquitoes exposed to prallethrin, whereas exposure to sumithrin did not increase their exposure to the ULV droplets. The location of droplets on mosquitoes, the effects of droplet volume, and subsequent mortality are discussed.