Evaluation of Tracer dyes for spray deposit assessment in the vineyard

Results are reported from a series of experiments performed to assess the suitability of 12 tracer dyes for sprayer deposit assessment: five fluorescent and seven non-fluorescent tracer dyes were tested.Tartrazine and Amaranthus proved to be the best tracers because of no toxicity, low cost, simple laboratory procedure, photostability, and high recovery rate from both artificial and natural targets.Results are also reported of the use of two different dyes on the same target, aiming at reducing the number of samples: analysis of the data in the specific test showed no significant difference between the use of two dyes on the same target, in comparison to a dye taken individually.In the field test with regard to the distribution the average deposition is about 54% with ground losses of about 26% and hidden losses (mostly drift) were about 20%. As far as the distribution is concerned, a significant difference was found for the height analysis, where the greatest amount of tracer was found on the leaves placed in a high position.With regard to exposure, all the differences were significant, with the greatest amount of tracer being found on the best exposed leaves and the least on those in the interior of the vegetation. The anova test shows that the two tracers did not show significant differences between them while the factors taken into account do, which means that they can basically be used together without affecting the significance of the factors that do show significant differences between them.