Modern hydraulic-based FSDS layouts: impact of vine growth stage and canopy density on spray performance

Fixed spray delivery system (FSDS), an alternative to conventional pesticide technologies, is gaining interest in grapevine. Indeed, especially in steep-sloped vineyards, optimal configured FSDS layout can enhance operator safety and potentially provide adequate spray performance. This study compared the spray performance of two modern 2-tier hydraulic-based FSDS layouts (L1 and L2), tailored to a vertical shoot positioning-trained vineyard. The investigation was conducted across three vine growth stages, with two canopy densities evaluated at each stage. Spray performance was assessed in terms of canopy deposits, in-field ground losses, and the impact of the plant protection product (PPP) wash-off effect caused by water used as propellant. Results were compared with field data obtained under comparable conditions using a conventional airblast sprayer. With respect to L1 layout, L2 layout achieved across the growth stages 1.75 and 1.55 times more canopy deposit and ground losses, respectively. Moreover, the L2 layout resulted in a more uniform canopy deposit within the sampled area resulting in a more promising HSD-FSDS configuration for grapevine spray applications. The PPP wash-off effect evaluation further supported this outcome but also identified areas for refinement to enhance spray performance. Based also on the comparison with the conventional airblast sprayer, recommendations for future protection plans are proposed, providing a step-forward toward large-scale adoption and implementation of HSD-FSDS technology