Improved systems of pesticide application

Abstract

More efficient transfer of pesticides to their intended biological targets is essential to reduce costs, to minimize the selection of resistant pests and to avoid environmental pollution. Most pesticide formulations are diluted in water and applied as sprays with a wide range of droplet sizes. The hazard of down-wind ‘drift’ of the smallest droplets is increased by evaporation, while most wastage is due to the largest droplets, which are poorly retained on most targets. Spray retention is improved by using narrower droplet-size spectra appropriate for particular targets. This permits reduction of spray volumes, use of less volatile formulations and more rapid and timely application in relation to pest infestations. Increased deposition on undersurfaces of leaves is achieved by controlling trajectories of electrostatically charged droplets. New low-energy systems to deliver ultra-low volumes of charged sprays will improve integration of chemical with biological controls and will eliminate hazards associated with preparation of sprays.