Characterization of pesticide dispersion from aerial applications of mosqui adulticides: Meteorological effects and canopy penetration

摘要

Aerial Adulticiding is a necessary tool which plays a vital role in the prevention of vector borne diseases. There is however, pressure upon the public health community to optimize applications both in terms of mosquito control, and non target health.We have therefore investigated the dispersion of permethrin at two application altitudes (30 and 45 m.)over a range of typical atmospheric conditions. Chemical dispersion was physically characterized and biologically assayed as both flux and deposition.Wind speed fluctuations were measured via four separate sensor groupings: Three dimensional sonic anemometers within (2 m) and at 2x canopy height (7 m): Two dimensional snemometers within (2 m) and at canopy top (3m): Propeller anemometers at 2 m in the open, and at application altitude via a kitoon system (30 and 45 m): Aircraft mounted sensors at the delivery zone (30 and 45 m). Data is presented on the physical and biological characterization of spray dispersion. Overall there was little differencein wind speed from one test to the next. There was however, a clear difference in atmospheric turbulence during treatment nights. The effect of stability on deposition and flux differed as altitude changed. When non-target mortality was high at 30 m application altitude the conditions were stable, and large volumes of pesticide descended via aircraft vortices and sedimentation. Overall the 45 m application altitude did not produce excess non target mortality regardless of stability at time of application. Neutral conditions with increased turbulence provided more operative control as effective flux.