Field Measurements of Spray Drift in Strawberry

Passive drift samplers were mounted on a frame, attached to the sprayer, at 2 m behind the nozzles of different strawberry spraying systems. The spraying systems were operated at a common tractor speed of 2 m/s. The drift samplers were made of cotton and acryl thread of 2 mm diameter, 3 m long and these were mounted horizontally on a frame at different heights up to 2.0 m above the ground. Comparing measurements at different growth stages (1. in May and 2. in August) demonstrated that drift was reduced by 75% due to the increased filtering effect of the leaf density in August. The drift from a tunnel sprayer was 10 and 13% of a reference sprayer when using an end-curtain and 55% and 37% without any end-curtain at growth stages 1 and 2, respectively. At growth stage 1, using 80 015 nozzles at 200 mm from the plants gave a significant increase in drift compared with the similar nozzles at 100 mm from the plants. At growth stage 2 the reference sprayer at 1.0 MPa gave a significantly higher drift than at 0.5 MPa. Using AI nozzles reduced the drift significantly