SPRAY DISTRIBUTION AND RECOVERY IN CITRUS APPLICATION WITH A RECYCLING SPRAYER

Abstract

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