Droplet size and effectiveness on Aedes aegypti of an ULV adulticide-larvicide formulation using different solvents

LAURA HARBURGUER; ALEJANDRO LUCIA; EMILIA SECCACINI; SUSANA LICASTRO; EDUARDO ZERBA; HÉCTOR M. MASUH

Los Angeles

Congreso; 21st Latin American Symposium at the 77th AMCA Annual MeetingAmerican Mosquito Control Association Congress; 2011

AMCA

One of the most common methods for controlling arthropod vectors, particularly mosquitoes, is the application of insecticides by ground sprayers. When selecting spray equipment and insecticides, factors such as the recommended dose, the droplet size, the moving speed of the vehicle, the sprayer cost, etc., are very important. Droplet size is one of the most significant factors that affect how well a vector control application works, and depends, among other factors, of the solvent used. The use of gasoil as solvent is often recommended, invoking better insecticidal effect, more aerosol dispersion and high visual impact at the time of application. In this work we measure the droplet size during application of an ULV formulation containing permethrin as adulticide and pyriproxyfen as larvicide. This formulation was applied with a thermal fogger using water, diesel or biodiesel as solvents, and as water-based cold fogger. We evaluated the effectiveness of these formulations on late 3rd or early 4th instars larvae and adults of Ae. aegypti in semi-field scale and in a field trial performed in Puerto Libertad, Misiones, Argentina. We found that the average droplet size of aqueous formulations was higher than oil-based ones. All formulations were equally effective on adults at all distances tested; however the effect on larvae mortality, measured as emergence inhibition (%EI) was higher for the aqueous formulation.