Skip to main content
ARS Home » Midwest Area » Wooster, Ohio » Application Technology Research » Research » Publications at this Location » Publication #374833

Research Project: Coordinated Precision Application Technologies for Sustainable Pest Management and Crop Protection

Location: Application Technology Research

Title: Evaluation of PWM technologies for pesticide spray applications in a two-year old apple orchard

item SALCEDO, RAMON - The Ohio State University
item Zhu, Heping
item ZHANG, ZHIHONG - Kunming University Of Science And Technology
item WEI, ZHIMING - Shandong Academy Of Agricultural Sciences
item Chen, Liming
item OZKAN, ERDAL - The Ohio State University

Submitted to: Proceedings of the American Society of Agricultural and Biological Engineers International (ASABE)
Publication Type: Proceedings
Publication Acceptance Date: 6/1/2020
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Utilization of pulse width modulation (PWM) controlled nozzles may mitigate the off-target losses generated during pesticide treatments. Assays in two-year old apple trees were conducted to evaluate spray quality in a single pass of three systems retrofitted in an airblast sprayer: 1) constant-rate with PWM nozzles controlled with a manual emission system; 2) variable-rate with PWM nozzles controlled automatically with a laser-guided intelligent spray system and 3) constant-rate without PWM controls. Stainless steel screens and water sensitive papers were selected as collectors for measuring the spray deposition and coverage on twelve trees randomly selected from four downstream rows. Plastic plates placed on the ground and nylon screens mounted at five heights on seven poles were used to assess ground and airborne drifts. Data showed that a single pass for each system provided adequate leaf deposits and coverage for the first two rows, but the disabled and manual PWM mode probably incurring over-spray problems. The variable-rate mode guaranteed a minimum number of droplets per unit area with a better relationship between deposition-coverage and the lower application rate. The automatic PWM control mode showed a better behavior in the ground and airborne drifts than the manually controlled PWM mode. Results suggested that a single spray pass from each of the three systems could provide adequate spray deposits and coverage in the first two rows, reducing economic costs, but the automatic PWM control could reduce more off-target losses, contributing more efficient spray applications than both conventional and manual PWM controlled constant-rate systems.