Spray Drift and Off-Target Loss Reductions with a Precision Air-Assisted Sprayer

Abstract

Abstract. Spray drift and off-target losses are inherent problems of conventional air-assisted sprayers; consequently, their low efficiencies cause environmental pollution and public anxiety. A new drift reduction technology incorporating laser scanning capabilities with a variable-rate air-assisted sprayer was developed to address these problems. This new sprayer, the same sprayer with the variable-rate function disabled, and a conventional constant-rate air-blast sprayer were tested for comparison of spray drift and off-target losses in an apple orchard. Tests were conducted at three different growth stages: trees just beginning to leaf (leafing), half foliage, and full foliage. Spray deposits from spray drift and off-target losses were collected within tree rows at ground level, above and behind the sprayed trees, in the spaces between trees, and from 3.2 m tall poles at 5, 15, and 35 m from the tree rows. Compared to the constant-rate sprayers, the laser-guided variable-rate sprayer reduced average spray losses on the ground by 68% to 90% and around tree canopies by 70% to 92%, reduced airborne spray drift by 70% to 100%, and most importantly, reduced the spray volume by 47% to 73%, while spray deposition quality inside the canopy for these sprayers was comparable. These results demonstrate that the variable-rate sprayer incorporating the innovative laser scanning technology reduced spray drift and off-target losses of pesticides, was environmentally sustainable, and was economically beneficial to growers.