“…In addition, it is difficult to generate a good contrast between the droplets and the surface of leaves because of their darkgreen colour. For these reasons, researchers have used small portions of white polyvinyl chloride (PVC) sheets as artificial targets to simulate the behaviour of citrus leaves (Vidal et al, 2003;Chueca et al, 2010;Garcerá et al, 2011) since previous work showed that these collectors did not show statistically significant differences in coverage percentage, number of impacts per square centimeter and mean area of the impacts when compared to citrus leaves (Mercader et al, 1995). Despite this important advantage, PVC collectors are very difficult to handle in the field, because droplets formed on their surface easily slip, as happens on leaves, which changes the apparent distribution of impacts, and their use is often restricted to the laboratory.…”