Restriction of Application Losses during Aerial Sprayings1

Results are reported on the prevention of losses of pesticide liquids due to droplet drift during aerial spraying. The effect of two basic factors was tested: a) change in drop size achieved either by use of different nozzles or by their modification or by regulation of the physical properties of the pesticide liquids; b) change of external conditions of drop fall achieved by the regulation of flight altitude, arrangement of nozzles on the aircraft, accuracy of operation of the spraying equipment The experiments proved that droplet size was most affected by use of TeeJet nozzles with Sabatka terminals, and to a lesser extent by the Lo-Drift agent Both factors limited the formation of the smallest drops, up to 100 μm especially. Accurate operation and maintenance of the spraying equipment (especially timely turning off at the end of lanes) has a great effect on limiting drift Optimum flight altitude (according to wind speed) is a compromise between the effort to limit drift and droplet evaporation and the achievement of required uniformity of deposition (CV). With the Z-37 aircraft, the optimum flight altitude in good weather conditions is about 4-5 m. Earlier experiments (to 1978) indicated good results with the addition of Ulvapron agent (21/ha) and Trition CS 7 (0.3%) mainly in warm (above 20°C) and dry (below 60 % R.H.) weather.