Indoor test bench measurements of potential spray drift generated by multi-row sprayers

The drift containment during spray application of plant protection products is essential to realize sustainable pesticide application accomplishing the recent EU directives and strategies. In these last years, an alternative methodology for quantifying the potential drift generated by different types of airblast sprayers used to apply one-row per pass was developed. The methodology foresees the use of an ad hoc test bench conducting trials in absence of target and in calm/absence of wind. In these conditions the test bench device allows to collect and quantify the spray fraction that remains suspended over the test bench immediately after the sprayer passage and that can potentially be carried out of the target zone by environmental air currents. In this context, in order to enlarge the application of this methodology to a wider range of spray application techniques, the suitability of the test bench and its methodology was verified also for multi-row sprayers. Conventional (Diva model - Ideal S.r.l.) and pneumatic (Supra model - Ideal S.r.l.) multi-row sprayers were tested in two versions, namely two and three rows applied simultaneously. Furthermore, the two versions of the conventional sprayer were tested using both conventional and air inclusion nozzles. Finally, the configurations tested were classified according to their potential drift reduction compared to a reference spray equipment. The results indicate that the test bench methodology represents a feasible method to measure the drift potential also for the multi-row sprayers discriminating between the number of rows applied simultaneously and nozzle types. The standardization of spray deposits, based on the spray specific output parameter, allowed a broad comparison of drift potential values obtained irrespective of spray application technique, that in some cases implies big differences in the volume applied.