Assessment of Three Commercial Over-the-Row Sprayer Technologies in Eastern Washington Vineyards

Washington winegrape growers are rapidly adopting vineyard management technologies such as mechanical pruners and harvesters, but they have been slower to adopt new chemical application technologies. This study generated technical information about commercial over-the-row sprayers and their deposition and drift to allow growers to select and optimize sprayers for different vineyard systems and winegrape canopies. Three commercial sprayer technologies (multi-fan heads, pneumatic, and electrostatic) were evaluated for canopy deposition and drift in the 2016 and 2017 production seasons. Data were collected in Vitis vinifera Chardonnay and Riesling vineyards at two application timings, early season and midseason, to determine sprayer deposition patterns in opposed and unopposed applications and in-field aerial and ground drifts. All sprayer technologies showed consistent in-canopy deposition and drift patterns at both application timings. Regardless of sprayer technology, the most deposition was in the upper canopy rather than in the fruiting zone. Similarly, the most aerial and ground drift occurred in the row closest to the sprayed row, indicating that drift is relatively low with all three evaluated sprayer technologies.