SUSCEPTIBILITY STATUS OF AEDES AEGYPTI POPULATIONS TO NALED IN COLLIER COUNTY, FLORIDA

The continued efficacy of adulticide products is critical for effective mosquito control and rapid response during arboviral disease outbreaks. In Collier County, Florida, documented pyrethroid resistance in Aedes aegypti has increased reliance on other chemistries, including products containing the organophosphate naled. To evaluate current susceptibility status to naled, 7 Ae. aegypti populations were collected from "hot spot" locations in Collier County between 2022 and 2026 and assessed using the Centers for Disease Control and Protection Bottle Bioassay. Five populations, including all residential and commercial sites, were classified as susceptible. One population collected from a tire shop demonstrated developing resistance in both 2022 (93.75%) and 2023 (92.49%), while a golf course population exhibited confirmed resistance in 2022 (52.23%) but shifted to developing resistance in 2023 (90.43%) following site redevelopment. Although most populations remain susceptible, the detection of localized reduced susceptibility highlights the dynamic nature of resistance and the importance of continued comprehensive monitoring. These findings suggest that naled should be used with caution against Ae. aegypti, particularly during arbovirus outbreaks where rapid and reliable vector suppression is essential, and support the need for proactive resistance management and insecticide rotation strategies to preserve operational efficacy.