Assessment of Anopheles quadrimaculatus response to permethrin and resmethrin by topical application

Topical applications with field-captured mosquitoes provided LD50 estimates ranging from 13.3 to 20.0 ppm for permethrin and 8.5 to 18.9 ppm for resmethrin in the Stuttgart, AR, area in 1993. Mosquitoes collected from the abatement area appeared to be more susceptible to resmethrin than those from outside the area (8.5 ppm vs. 18.9 ppm). The observed difference was not great enough to be of concern from an economic or control standpoint. The data provided a firm baseline for future assessment of changes in susceptibility to these 2 materials. Mosquitoes collected in Walnut Ridge, AR, were susceptible to permethrin and resmethrin within the same range as the Stuttgart populations, but the limited number of observations preclude firm LD50 estimates.