Results of spray drift experiments are presented for the effect of an insect net of equal height as the crop positioned at the outside of an orchard (3 m from the last tree row) and the combination of this insect net connected to a closed rain shield above the fruit crop. Spraying was done with a conventional crossflow orchard sprayer (Munckhof ECO cap) equipped with Very Fine standard hollow cone nozzles (Albuz ATR Lilac; 7 bar) and with a 95% drift reducing technique (DRT95). The DRT95 was the same sprayer but equipped with 90% drift reducing nozzles (DRN90; Albuz TVI8001, 9 bar), low air setting of the fan gear box and one-sided spraying of the outside tree row (only from outside inward). During the spray drift experiments the downwind outside 24 m of a cherry orchard was sprayed at the full leaf stage (BBCH 90/92) using the fluorescent tracer Acid Yellow 250. Spray drift deposition was collected downwind on a mowed grass area up till 25 m distance from the last tree row. Airborne spray drift was measured at 7.0 m distance from the last tree row on a pole at which two lines with collectors were attached at 1 m spacing up to 10 m height. At different zones for both application techniques the effect of the insect net on spray drift reduction was on average 53%-57% in comparison with both the spray application in the open situation. The spray drift reduction of the combination insect net at edge of field and closed rain shield above the fruit crop was on average 89%-92% for the two application techniques at different zones outside the treated field.Airborne spray drift (0-10 m height at 7 m from last tree row) was reduced by positioning an insect net at 3 m from the last tree row with 26% for the standard spray application and 96% for the DRT95. The combination insect net at edge of field connected to the closed rain shield above the fruit crop resulted in airborne spray drift reductions of 67% for the standard application technique and 97,6% for the DRT95.
|Name||Rapport / Stichting Wageningen Research, Wageningen Plant Research, Businessunit WUR Open Teelten|