Effect of air-jet configuration on spray coverage in vineyards

A new type of sprayer developed for orchard is being adapted for vine spraying. The technology uses vertical air sleeves, generating a two-dimensional horizontal air jet, to distribute spray droplets within the canopy. Three different configurations were tested to determine the combination which provides the most appropriate spray distribution within the canopy along with the highest coverage on artificial cylindrical targets. One configuration (a) used a single air jet perpendicular to the row. Two other configurations used a pair of sleeves, one sleeve on each side of the row. In configuration (b), airflow rate was distributed evenly between the two sleeves. In configuration (c), the distribution of air was varied along with the angle of attack, providing an interaction between the two airflows. Coverage on 22 mm cylindrical targets covered with water-sensitive papers was evaluated across the vine rows. These papers were processed using image analysis. Results showed that coverage was maximised using configuration (c). The use of a pair of sleeves, in configurations (b) and (c), provided a more uniform distribution of droplets locally. Crown Copyright (c) 2004. All rights reserved Published for Silsoe Research institute by Elsevier Ltd.