Adjusting Air-Assistance and Nozzle Style for Optimized Airblast Sprayer Use in Eastern Washington Vineyards

Abstract

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 winegrape 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 most total collected canopy deposition when using air-assistance during the early season, but had the most 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, using the air induction nozzle without air optimized 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, such as using air induction nozzles and/or turning air-assistance off, to determine which are best suited for their farming practices. Such an approach will allow better optimization of the sprayer for their vineyard spray application needs and reduces possible negative impacts associated with off-target chemical deposition on humans and the environment.