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

Abstract

Air assisted orchard sprayers are characterized by a strong airflow that carries the pesticide droplets to the target canopy and assist in moving the plant parts to allow deposition throughout the whole tree. It has been shown before that different designs of orchard sprayers result in different airflow profiles, but it is still unclear whether these differences strongly affect on-target spray distribution, and what is the role of tree architecture. Here we present an in-field analysis of the on-target deposition profiles from three distinct sprayer types in trees of four different apple and pear training systems. 2The results obtained showed that there was a strong relationship between the vertical leaf deposition profile and the outlet air flow pattern from the sprayers. Stronger air assistance (higher air speed) was directly correlated to a higher on-target deposition. It was also observed that directing nozzles towards the target is always an advantage irrespective of tree architecture.Tree characteristics such as total leaf cover, leaf wall porosity and tree volume strongly affected the total on-target deposition, further confirming previous claims that ground surface area alone is an incorrect measure for dose calculation in fruit trees.

Ground Deposition and Airborne Spray Drift Assessment in Vineyard and Orchard: The Influence of Environmental Variables and Sprayer Settings

“…Similar to the vineyard, the apple tree canopy is also characterized by own shape, dependent on tree training, and consequently own porosity. These characteristics affect the fate of pesticide droplets inside the plant micro-environment which directly determines the efficacy of treatment and indirectly it also determines the off-target losses [43]. The airborne spray drift deposition (Figure 10a) shows the effect of configurations tested at 5 and 10 m to the sprayed area.…”

“…Although the influence of crop type [42] and its growth stage [99] is that primarily studied and related to the spray drift amount, nowadays it is likewise clear that the spray drift amount also depends on the complex of architecture and geometry of cultivation [44,[100][101][102]. The architecture varies with the training systems (pruning and training technique) affecting both deposition and off-target losses [43]. The probable effect of canopy structure is confirmed by the shape of the airborne spray drift profile observed at 5 and 10 m from the sprayed area and plotted in Figure 7: (a) mean values and (b) 90th percentile.…”

Canopy spray deposition and related mortality impacts of commonly used insecticides on Drosophila suzukii Matsumura (Diptera: Drosophilidae) populations in blueberry

“…Our results focus attention on the importance of using directed or targeted sprays to optimize pesticide application . Each of the respective sprayers has unique benefits and drawbacks.…”

“…Chemical control is the most prominent way to prevent D. suzukii damage with an average of five to eight chemical applications per growing season . Canopy architecture can strongly affect spray deposition due to the compact nature of the canopy in many crops, resulting in uneven deposition of spray droplets, especially within the inner and lower canopy . Therefore, it is essential to choose appropriate spray equipment that provides relatively uniform spray deposition in all portions of the plant canopy.…”

Outcomes on the Spray Profiles Produced by the Feasible Adjustments of Commonly Used Sprayers in “Tendone” Vineyards of Apulia (Southern Italy)

“…A correctly adjusted sprayer guarantees that the spray mixture is addressed to the target, minimizing the risks for the environment (e.g., spray drift) and for consumers [3][4][5][6]. Conversely, in order to improve the efficiency of plant protection product (PPP) applications, the sprayer adjustment must be in agreement with the crop growth stage [7][8][9], the pesticide formulation [10][11][12], and the specific morphological characteristics and canopy patterns of the vineyard [13][14][15][16][17][18][19][20]. One of the main and crucial steps to adjust sprayers for bush and tree crops is represented by the evaluation of the spray profile,…”