Drift potential from a solid set canopy delivery system and an axial-fan air-assisted sprayer during applications in grapevines

Solid set canopy delivery system (SSCDS), consisting of fixed spray micro-emitters distributed throughout the tree or vine crop canopy, has the potential to reduce off-target spray drift and deposition because they do not use air-assistance for spray delivery. This study evaluated two different SSCDS configurations and a conventional axial-fan air-assisted sprayer for drift potential in a modified vertical shoot position trained vineyard. The application systems were evaluated using 500 ppm solution of Pyranine 10G (R) as a fluorescent tracer. Spray was captured on mylar cards and water sensitive paper (WSB) samplers downwind the spray row. Samplers were placed above the canopy and on the floor between the vine rows. Spray material collected on mylar cards was quantified by fluorometry, and coverage was estimated by processing pertinent WSP images. Overall, the air assisted sprayer had significantly higher losses to the ground and airborne spray drift compared to the two SSCDS configurations. The SSCDS had minimal amounts of spray losses to air (<1 ng cm(-2)). Similarly, off-target spray movement was confined within 4.5 m downwind of the sprayed row. However, no significant difference in ground runoff was observed among the studied spray systems. (C) 2019 IAgrE. Published by Elsevier Ltd. All rights reserved.