Associate Professor East Carolina University, North Carolina, United States
Abstract: Insecticide resistance is increasing globally, posing challenges to mosquito control programs (MCP) that protect public health. Conventional efficacy evaluations rely on field evaluations of formulated adulticide products (FP), which are logistically demanding and weather dependent. In contrast, the widely adopted Centers for Disease Control and Prevention (CDC) bottle bioassays are optimized for testing active ingredient residues rather than aerosolized FP, thereby creating a methodological gap between laboratory bioassays and operational field performance. The current study addresses this gap by characterizing aerosolized FP droplets in a novel compact wind tunnel using instrumentation analogous to that employed in field evaluations. Wind tunnel settings (e.g., air pressure, wind speed, and FP feed rate) were standardized based on droplet counts on slides in field evaluations conducted at different distances (31, 61, 91 m) downwind from the spray line. Knockdown and mortality rates were assessed for Aedes albopictus and Culex pipiens/quinquefasciatus exposed to FP in the wind tunnel. Calibration curves were derived based on the relationship between droplet counts on slides and mosquito mortality rates. Ultimately, the goal of the wind tunnel platform is to provide MCP with a reproducible, laboratory-based method for evaluating FP efficacy, thereby bridging the methodological discontinuity between CDC bottle bioassays and field-scale operational decision-making.
