SPRAY DISTRIBUTION AND RECOVERY IN CITRUS APPLICATION WITH A RECYCLING SPRAYER

A prototype sprayer, based on the Canadian RECUPAIR concept, was evaluated under three citrus grove conditions. Spray droplet recovery was measured in an open area (without trees) and with small grapefruit and orange trees as well as very small orange trees. Spray recovery was 61% of the total volume sprayed when the sprayer was operated in a stationary mode with no trees. Spray recovery in the citrus grove ranged from 22% to 45%, depending upon the average tree size and the orientation of the sprayer to the wind. Spray deposition within tree canopies was evaluated through visual assessment and image analysis of water–sensitive papers. Deposition was similar in the vertical sample locations on both sides of the tree. The center of the canopy received about half the quantity of spray deposited at the outside of the trees. The results show that the RECUPAIR concept could be useful in spraying small citrus trees with gaps between adjacent trees.