Quality of spray distribution in vineyard using a new low-drift pneumatic nozzle

The efficiency of treatments in vineyards largely depends on the necessary balance between leaf coverage and spray drift containments. Recently a pneumatic nozzle able to consistently increase the droplet size spectra, without changing the liquid flow rate and fan air speed, was developed. However, it is questioned if the use of a low-drift pneumatic nozzle might not provide adequate spray deposition and coverage; so, the objective of the work was to assess the capability of this nozzle type to guarantee similar canopy deposition and spray coverage to that obtained using the standard pneumatic nozzle. For these purposes the multiple-row pneumatic sprayer Cima 50 Plus 400L equipped with spray head ”2 hands-2 cannons” was used in three configurations deriving from the combination of conventional hand-type nozzles with modified cannon-type nozzles able to vary the insertion position of the liquid hose. In particular, the configurations differ by each other for the diameter of spout at release points in the cannon-type nozzles: at 50 and 70 mm inside diameter position and at 280 mm outside of the spout. For each configuration a spray application of two vineyard rows (full growth stage) was performed using the same application rate (200 L ha-1). The canopy spray deposition and coverage were sampled in different positions along the rows at different canopy heights and depths using artificial collectors, filter papers and water sensitive papers respectively. In general, the canopy spray deposition increases up to 20% when the low-drift pneumatic nozzles are used. At the same time the canopy coverage did not differ among the tested configurations; in general, an average of 20% and 7% of collector surface covered were measured for the upper and under leaf sides respectively. Based on these experimental field results, the use of low-drift pneumatic nozzles guarantee the same level of canopy spray deposition and coverage compared with a conventional pneumatic spray application.