Quantitative Analysis of Aedes albopictus Movement Behavior Following Sublethal Exposure to Prallethrin

The pyrethroid prallethrin, an AI in DUET™ (Clarke Mosquito Control, St. Charles, IL), is widely marketed ultra-low volume (ULV) mosquito adulticide. Volatilized prallethrin is intended to stimulate mosquito flight, increasing its adulticide effectiveness. However, field tests using volatilized prallethrin have not produced significant differences in mosquito trap catches, leading to questions regarding prallethrin's behavioral impact efficacy. Thus, we conducted laboratory tests of prallethrin's effect on flight behavior of adult female Asian tiger mosquitoes, Aedes albopictus. Mosquitoes were divided into 3 groups: untreated control, exposed to volatilized prallethrin, and exposed to a liquid spray calibrated to simulate a ULV application at label rates. After exposure, mosquito behavior in an airstream of 0.5 m/sec was recorded and analyzed using motion-tracking software. No significant differences in flight behavior were found between the control and treated mosquitoes exposed to volatilized prallethrin. The ULV-sprayed mosquitoes exhibited a significant increase in the number of flight events, the turning frequency, overall movement speed, and flight speed compared to the control-a significant difference in locomotor stimulation response that would increase exposure to a ULV spray cloud. However, our results showed that volatilization alone was insufficient to increase ULV efficacy in the field and suggested that incorporating a more volatile flight stimulant into ULV adulticides would provide a measurable improvement in mosquito control.