Driftmetingen KWH Mistral Boomgaardspuit 2020-2021

Results of spray drift experiments are presented of the KWH Mistral cross-flow fan orchard sprayer in comparison with a reference spray technique for fruit crop spraying in The Netherlands. The KWH Mistral sprayer was equipped with controllable air settings and drift reducing nozzles (Lechler ID 90-01 C at 5 bar spray pressure, 90 % drift reduction), the PTO of the tractor, controlling the fan speed, was limited to 300 rpm and the sprayer gear box was set to the low air setting. The KWH Mistral orchard sprayer used a specific protocol for the outer five tree rows, using no air support out of the orchard and spraying the outer tree row from one side. During the spray drift experiments, performed in 2020 and 2021, the downwind outer 24 m of an apple orchard was sprayed at the full leaf stage (BBCH 75-91) using the fluorescent tracer Acid Yellow 250. Spray drift deposition was collected downwind on a mowed grass area up to 25 m distance from the last tree row. For the KWH Mistral orchard sprayer spray drift reduction at 4.5-5.5 m distance from the last tree row was 98.0% in comparison with the reference spray application.