Optimized Aerial Applications of Two Resmethrin Formulations Against Caged Anopheles quadrimaculatus

Optimized aerial applications were conducted to assess the efficacy of 2 formulations of resmethrin (Scourge® 18–54, Aqua-Scourge® 10–30) for control of caged adult Anopheles quadrimaculatus. Micronair® AU4000 rotary atomizers were employed to apply the chemical. Both compounds were applied at 0.0035 lb AI/acre (3.92 g AI/ha) with the use of the AGDISP computer model to predict appropriate flight offsets (up to 1,219.2 m). Efficacy was based on bioassays with caged An. quadrimaculatus adults and assessment of impinger-collected droplets. Both compounds provided effective mosquito control. Mean mortality at 24 h posttreatment averaged 80.4% for Scourge, and 80.7% for Aqua-Scourge. Mean droplet sizes, Dv0.5 = 26 µm and 38 µm, and mean density, 74 droplets/cm2 and 41 droplets/cm2, for Scourge and Aqua-Scourge, respectively, were consistent with the bioassay results. Analysis of droplet deposition and mortality failed to reveal a statistical correlation between mortality and deposit volume.