Evaluation Of Spray Drift With An Experimental Ultrasonic Sensor Sprayer In A Dwarf Apple Orchard

Dwarf apple trees are becoming more common in advanced apple orchards due to their easier maintenance and more efficient production. However, this may increase the risk of spray drift if orchardists’ do not adjust spraying practices to match shorter dwarf varieties of fruit trees as compared with larger more traditional canopies as dwarf trees have less foliage to intercept spray. Two studies were carried out to examine the off-target movement and total spray usage of the spray from a conventional air-blast sprayer as compared with two experimental sensor sprayers using either ultrasonic or LiDAR technology. The experimental sensor sprayer was set to spray only when canopy was present. The first study assessed three treatments including a conventional orchard sprayer and a single row ultrasonic sensor sprayer with sensors either ON or OFF. The second study assessed the total usage of spray at a time when no canopy was present using the same ultrasonic sprayer as well as a high resolution LiDAR scanner. An application volume of 500 l/ha was selected for both studies. Results found that with the ultrasonic sprayer drift was reduced 24% compared to the conventional treatments. Further, when no canopy was present, a 22% and 28% total reduction of spray was observed using the LiDAR and ultrasonic sprayer, respectively.