First Steps Towards a Standardized Methodology for Indoor Measurement of Spray Mass Balance for Vineyard Sprayers

During plant protection product (PPP) spray application, droplets can meet different ends. A fraction deposits on target, another one will end-up as ground and atmospheric losses. The investigation of the different spray fractions allocation is useful to i) assess treatment efficiency and, ii) select the proper sprayer adjustment. To this extent, a dedicated methodology to assess in indoor conditions the spray mass balance is currently being studied by the DISAFA (University of Torino), IFV and INRAE (France). An artificial target to mimic two vineyard canopy rows is used to collect and quantify the spray canopy deposit. A test bench surrounding artificial rows is used to hold collectors so that the spray passing through the artificial vine canopies and the portion of spray cloud directed to the atmosphere over the rows can be collected. Collectors are also placed on the ground to measure ground sediments between rows. The system was used to measure the spray mass balance of an airblast sprayer by applying a solution of water and Tartrazine used as tracer. Two vineyard growth stages were simulated and compared. Results showed deposits on target ranging from 38.7% to 54.5% (early and late growth stage respectively). Mixture recovery ratio (to target + losses) was always close to 100%. Therefore, the methodology offers good perspectives in view to propose a standardized methodology for spray mass balance assessment in 3D crops.