A comparison of methods for assessing vertical spray distributions from air‐assisted sprayers

Three Centres in Friuli (northern Italy) are offering voluntary testing services for vineyard sprayers. Test procedures routinely include the assessment of vertical spray distribution, using special test rigs. The objective of this research was to compare the vertical distributions as obtained from: patternator (a) (rectangular plates); patternator (b) (lamellate spray separator); spherical spray collectors and fluorimetry. The results showed that both patternators greatly underestimated the portion of spray directed above 3.0 m from the ground. The bulk of the spray was constantly found in the height range of 0.5 m to 1.2 m, which was 0.4–0.5 m lower than by the fluorimetric method. Thus, both patternators can produce substantial errors when used to calibrate a vineyard sprayer, and this may explain some unsatisfactory results previously found.