This work deals quantitatively with the generation, dispersion, and deposition of pesticide droplets on vegetation and with off-target drift of undeposited droplets. A computer simulation model for calculating dispersion, deposition, and drift is described, with comparisons between calculated results and field measurement results. The model includes the effects of aircraft vortex, atmospheric turbulence, droplet evaporation, and droplet deposition on foliage. Model output includes values of droplet deposit density and size on foliage and ground as well as droplet concentration and size in the...