FOLIAR DEPOSITION AND PESTICIDE LOSSES FROM 3 AIR-ASSISTED SPRAYERS IN A HEDGEROW VINEYARD

Three commercial air-assisted sprayers were tested in a hedgerow viney ard, at full vegetative development (end of July; leaf area index = 1. 94), using a water-soluble food dye as a tracer. The spraying equipmen t used was (1) a high-volume (1355 l ha(-1)) axial-fan sprayer; (2) a low-volume (246 l ha(-1)) compressed-air sprayer (3) a sprayer fitted with deflectable ail outlets, allowing an adjustment of the output ang le, relative to the row direction, from 90 degrees to 118 degrees. All application techniques appeared to be capable of delivering more than 64% of the sprayed material onto the leaves and grapes. The high-volu me sprayer provided the most uniform distribution over the foliage. Th e change of the output angle from 90 degrees to 118 degrees did not si gnificantly affect total leaf deposition, but increased the overall va riability of the deposits. Copyright (C) 1996 Elsevier Science Ltd.