Development of Two Intelligent Spray Systems for Ornamental Nursery and Fruit Tree Crops

Current application technology for floral, nursery, and other specialty crop production wastes significant amounts of pesticides. Two different real-time variable-rate sprayer prototypes for ornamental nursery and tree crops were developed to deliver chemicals on target areas as needed. The first prototype was a hydraulic vertical boom spraying system that used ultrasonic sensors to detect tree size and volume, and the second prototype was an air-assisted spraying system that used a laser scanning sensor to measure the entire tree structure. The automatic controllers developed for the prototypes consisted of a computer program, a signal generation and amplification unit, and pulse width modulated solenoid valves. The controllers analyzed sensor signals and actuated the solenoid valves to automatically provide variable flows to nozzles based on tree characteristics and plant occurrence. Preliminary laboratory and field tests demonstrated that both prototypes had the capability to control spray outputs that continuously matched canopy characteristics in real time.