Droplet Stee for Low and Ultra-Low Volume Aerial Spraying

Abstract

Meteorological data from stations in Malawi adjacent to two cotton-growing regions and a simplified graphical analysis of the sedimentation and wind transport of droplets were used to predict the deposition of low- and ultra-low-volume aerial sprays of various droplet size distributions. A volume median diameter (VMD) of 100 mu m is recommended for ultra-low-volume application of non-systemic insecticides in solvents of low volatility, and one of 200 mu m for aqueous sprays at the conventional rate of 22 litres/ha. The theoretical results are discussed with reference to tests carried out in the 1969-70 Malawi cotton season.