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

Abstract

Washington wine grape growers are rapidly adopting vineyard management technologies such as mechanical pruners and harvesters but have been slower to adopt new chemical application technologies. Therefore, this study was aimed at generating technical information about commercial over-the-row sprayers deposition and drift, which could be used by growers during sprayer selection and optimization for different vineyard systems and wine grape canopies. Three commercial sprayer technologies, i.e. multi-fan heads, pneumatic, and electrostatic sprayer, were evaluated for their 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 mid-season, to determine sprayer deposition patterns in opposed and unopposed application spray row canopy and in-field aerial as well as ground drift. 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 compared to the fruiting zone of the vines. Similarly, the most aerial and ground drift was in the row closest to the sprayed row, indicating that drift is relatively low with the three evaluated sprayer technologies.