Assessment of orchard sprayers using laboratory experiments and computational fluid dynamics modelling

Spray deposition profiles in pome fruit trees: Effects of sprayer design, training system and tree canopy characteristics

“…The crossflow sprayer produced a peak at mid height of the canopy that is not present for the axial sprayer. We did observe only a small deposition peak on a patternator wall in indoor trials (Dekeyser et al, 2013) at 1.5 m height, while for the rest the vertical spray profile in this zone was relatively uniform for the cross flow sprayer. The deposition on a static uniform patternator wall, therefore, does not completely resemble the actual deposition process in real canopies, where differences in the vertical deposition are much more pronounced.…”

“…The crossflow sprayer gave a higher deposition than the axial sprayer for the training systems can, however, be adapted to improve uniformity, by adjusting the spout angles, as we have shown in previous work (Dekeyser et al, 2013). This could be important when targeting specific pests such as codling moth, which are mostly observed in the upper part of the tree crown (Losel et al, 2002;Simon et al, 2007).…”

“…The total air flow rates were estimated based on the air velocities measured at the air outlet and the corresponding surface area. The axial and cross flow sprayers produced an air volume flow rate of about 50,000 m 3 h −1 whereas the sprayer with individual spouts produced a lower air volume flow rate of about 13,000 m 3 h −1 ( (Dekeyser et al, 2013).…”

“…This sprayer was not tested for the pear Thedge training system. The sprayers were fitted with fully characterized Albuz (Saint-Gobain Solcera, Évreux, France) ATR hollow cone nozzles (Dekeyser et al, 2013). The axial and cross flow sprayers were equipped with 16 Albuz ATR orange nozzles of size 0.985 ± 0.0185 l/min and 0.98375 ± 0.019 l/min respectively.…”

“…In orchards, this is achieved using air assisted sprayers. Air assisted orchard sprayers use air jets generated by means of a fan to carry pesticide droplets, to displace the air in the crop canopy and to realize a homogeneous deposition on to the target canopy (Da Silva et al, 2006;Dekeyser et al, 2013;Delele et al, 2005;Escolà et al, 2013;Gupta et al, 2012;Khot et al, 2012;Sidahmed and Brown, 2001;Walklate et al, 1996). The pesticide deposition on the canopy can directly or indirectly be affected by the plant architecture, the physico-chemical properties of the pesticide, the meteorological conditions and the used spraying technique, among others (Catania et al, 2011;Celen et al, 2008;Cross et al, 2001;Dorr et al, 2013;Jaeken et al, 2001;Nuyttens et al, 2009;Pergher and Gubiani, 1995;Rosell and Sanz, 2012;Vallet and Tinet, 2013).…”