Crop-Specific Benefits of Air-Assisted Spraying in Pea and Parsley: Implications for Sustainable Pesticide Application

Improving spray deposition within crop canopies is important for sustainable pesticide application, particularly when target surfaces are shielded or located in difficult-to-reach canopy zones. Air-assisted spraying may improve droplet transport and canopy penetration, but its effect is likely to depend on crop structure and target-zone position. This study evaluated the usefulness of air-assisted spraying in pea and parsley using a prototype sprayer operated with and without airflow support. Spray deposition was assessed with water-sensitive papers positioned at crop-relevant heights in horizontal and vertical orientations. In pea, air assistance significantly increased deposition on vertically exposed surfaces; for example, on the approach side at 50 cm above ground, mean coverage increased from 0.0622 to 0.4491% (+621.9%). Its effect on upper horizontal surfaces was limited. In parsley, the response was more selective: deposition increased on vertical surfaces at 20 cm, but decreased on horizontal ones, including a reduction at ground level from 0.0928 to 0.0393% (−57.7%). These results indicate that the performance of air-assisted spraying depends on crop architecture, target-zone accessibility, and surface orientation. Within the limits of this two-crop study, air assistance appears most justified where improved canopy penetration or reduced ground losses are particularly relevant. The observed deposition differences should not be interpreted as direct evidence of biological efficacy.