Search

Spray deposits at various elevations within crabapple trees and on the ground were investigated with an air blast sprayer equipped with conventional hollow cone nozzles, air induction nozzles, and conventional hollow cone nozzles with a drift retardant in a commercial nursery field. Airborne deposits at three elevations on sampling towers and on the ground at several distances from the sprayer were also investigated with the three spray treatments in an open area without trees. Droplet size distributions across spray patterns were measured with a laser particle/droplet image analysis system. In general, there was no significant difference for deposits within nursery tree canopies and on the ground with three different spray techniques. With the 700 L/ha application rate, which was 360 L/ha lower than the rate normally used in nursery application, the tree canopies received over 4 to 14.5 times spray deposits actually needed from the air blast sprayer with the three spray techniques, and a large portion of spray droplets deposited on the ground.