Pesticides Deposition in Vineyards on Different Conditions of Leaf Wetness

Abstract

ABSTRACT:The high susceptibility to diseases of fine table grapes cultivars demand intensive use of pesticides, and the presence of water on the leaf surface can worsen the deposition of these products. The objective of this study was to evaluate the spray deposition in vine leaves in different conditions of leaf wetness, and test the effectiveness of an artificial ventilation method to remove water on the leaf surface. We evaluated the spray deposition in vine applied over: wet canopy (presence of high leaf wetness); canopy dried artificially (dried with air jet from air-assisted sprayer, wind speed of 25 km h -1 ) and canopy dried naturally (naturally dried leaves and free of water on its surface). Saline marker was used in the spray and the deposition on the canopy was determined by conductimetry. A pesticide application in vine, with the presence of water in the leaf surface, causes losses by run-off and reduces the deposit of spraying. The use of air jet formed by air-assisted sprayer fan is efficient for the removal of water on the vine leaf surface and its use can increase the favorable period for the application of pesticides without causing dilution and losses by run-off of the applied product.

Measurement of foliar spray retention on creeping bentgrass

“…However, no difference was observed between wet (80.0%) or dry (79.9%) leaves when sprayed at 750 L ha −1 . This finding was contrary to what had been observed on grape (Saab et al 2017) and the common perception that dew negatively influences foliar retention.…”

“…Additionally, dew is often present during spray applications on golf courses (Delvalle et al 2011;Williams et al 1998). Dew has been shown to reduce foliar retention on vine grapes (Vitis vinifera L.) by 75% (Saab et al 2017).…”