Adjusting Air-Assistance and Nozzle style for optimized Airblast Sprayer Use in Eastern Washington Vineyards

Summary Goals: There are many ways to optimize an airblast sprayer for use in vineyards. Three techniques growers use include: 1) changing nozzle type, 2) reconfiguring or adjusting the nozzles, and 3) adjusting the air-assistance to the droplets during an application. This study evaluated the effects of nozzle type and air-assistance use in airblast sprayers on canopy spray deposition and drift in a Washington wine grape vineyard that is trained to a modified vertical shoot positioning system. Key Findings: The one-piece nozzle with air assistance showed consistently high total collected canopy deposition regardless of time of season (early or mid-season). However, drift was reduced when air-assistance was not used. The air induction nozzle had the greatest total collected canopy deposition when using air-assistance during the early season, but had the greatest deposition mid-season without using air-assistance. Drift was reduced when air assistance was not used. Early in the growing season, maximum spray deposition in the fruiting zone of the canopy was achieved using air induction nozzles with air-assistance. However, if one adopted the use of air induction nozzle, without air, that would optimize fruiting zone spray deposition, while reducing captured aerial drift. Mid-growing season, maximum fruiting zone spray deposition without high drift was achieved using air induction nozzles without air-assistance. Impact and Significance: An airblast sprayer optimized through changes in nozzle or use of air-assistance can improve spray deposition into the canopy while minimizing drift. Growers can compare and adopt these drift-reduction techniques, i.e., using air induction nozzles and / or turning air-assistance off, to determine which are best suited for their farming practices. Such approach will allow better optimization of the sprayer for their vineyard spray application needs as well as reduce the possible negative impacts associated with off-target chemical deposition on humans and the environment.