Abstract
Studies were conducted in 1962 on the dispersal of granular insecticides by the Bell 47 G helicopter.
The helicopter was flown at a height of approximately 5 meters from the ground level along paths marked at intervals of 18 meters. The insecticides were applied from a spinning disc distributor at a rate of 30 kg per hectare. Sampling vessels were placed along lines laid at right angles to the line of flight paths to receive the granules as they fall.
The width of both up-and down-wind swaths obtained was about 18 meters, but the distribution pattern of granules was not similar between them. The distribution of granules within the swath was not uniform, and its seemed to be related to the size of granules and the mechanical composition of insecticide.
Of the components of the tested insecticides, a more uniform distribution was obtained from granules larger than 1.0 mm in diameter, then those smaller than 1.0 mm in diameter which showed tendency to fall in narrower width with greater variation of deposit across the swath.
