Further Development and Testing of a Compact Wind Tunnel for Exposing Mosquitoes to Formulated Insecticide Products

Area of Science:

• Entomology
• Public Health
• Pest Management

Background:

• Insecticide resistance is a growing global threat to mosquito control and public health.
• Existing methods like field trials are resource-intensive and weather-dependent.
• Current bioassays (e.g., CDC bottle bioassays) are not optimized for formulated products (FPs) used in aerosolized applications.

Purpose of the Study:

• To address the methodological gap in testing insecticide formulated product (FP) efficacy against mosquitoes.
• To evaluate the efficacy of four specific FPs against laboratory and wild populations of *Aedes albopictus* and *Culex pipiens/quinquefasciatus*.
• To determine if wind tunnel experiments can predict FP efficacy and inform the necessity of field trials.

Main Methods:

• Wind tunnel experiments were conducted to assess mosquito knockdown and mortality.
• Laboratory and wild populations of *Aedes albopictus* and *Culex pipiens/quinquefasciatus* were exposed to four FPs.
• The number of FP droplets deposited on mosquitoes was quantified and analyzed for correlation with mortality.

Main Results:

• Regression analyses indicated a significant relationship between droplet count and mosquito mortality for certain FPs.
• Wild *Culex* populations exhibited resistance to all tested FPs in the wind tunnel experiments.
• Low mortality rates (<90%) in wind tunnel tests correlated with likely mosquito resistance to the FP.

Conclusions:

• Wind tunnel experiments serve as a valuable screening tool for insecticide efficacy and resistance detection.
• Low mortality in wind tunnel tests suggests probable FP resistance, potentially obviating the need for field trials.
• High mortality in wind tunnel tests may warrant confirmatory field trials for specific FPs and mosquito populations.