Recent developments in the Evaluation of the Performance of Vineyard Sprayers

Vines are perennial crops that appear sensitive to various diseases and insects with a subsequent number of spray applications per year. In general, biological efficacy is strongly linked to the spray quantity and quality, assuming that non-intercepted droplets may lead to ground or atmospheric losses. This paper corresponds to a synthetic review focusing on need for generic methodology to assess vineyard sprayer deposition performance. Indeed, the deposition of droplets in a 3D canopy is a complex phenomenon that encompasses a wide range of variability that limits the capability for evaluating and for comparing field tests. Different levels of crop variability were identified among the cultivar, the development stage and the training strategy leading to a highly variable leaf area index over time. Other sources of variability depend on the sprayer technology where the air assistance and droplet emitters play a key role. Assuming the difficulties in the comparison of sprayers directly through field tests, the rationale for a fair and replicable comparison of sprayer deposition performance was developed by the joint unit UMT Ecotech between INRAE and associated technical institutes for vines (IFV) and fruit crops (CTIFL). An original methodology to assess sprayer deposition capability was developed based on an artificial vineyard whereas the potential spray drift of the complete sprayer is evaluated using an artificial wind generator. These test benches are now used in a purpose of official classification by French authorities.