Multi‐objective pesticide reduction‐oriented design optimization, atomization‐deposition performance and pests control efficacy of air‐assisted sprayers for dense‐planting spindle and V‐trellis pear orchards

BACKGROUND High‐density spindle and V‐trellis pear orchards face critical bottlenecks including complex canopies, poor sprayer adaptability, insufficient droplet penetration, uneven deposition, and low pesticide utilization. To overcome these issues, this study established a systematic framework including structure adaptation, parameter optimization, mechanism analysis, performance validation, and multi‐objective evaluation. A dedicated air‐assisted sprayer was developed using modular design, computational fluid dynamics (CFD) simulation, intelligent target detection, and high‐speed flow‐field visualization. The spray characteristics, air‐droplet coupling, and operational parameters were optimized and verified in laboratory and field tests. RESULTS The plant‐derived adjuvant decreased surface tension to 54.23 mN m −1 and contact angle to 49.68°, improving wetting and deposition significantly. The optimal system (60° deflector, 2200 rpm fan, 0.3 MPa pressure) produced stable wind speeds of 4.48–6.08 m s −1 and uniform droplets with a relative span < 1.1. Field deposition reached 3.82 μL cm −2 (V‐trellis) and 2.79 μL cm −2 (spindle). Control efficacy against major pests improved from 19–49.74% (1 day after treatment) to 39.91–72.41% (3 days after treatment). The optimized system reduced pesticide dosage by 25% while maintaining equivalent or better efficacy, with stabilized control up to 77.38%. CONCLUSION This study resolves the poor adaptability of conventional sprayers, reveals the air‐droplet coupling transport mechanism, and provides a technical scheme for precision green plant protection in dense pear orchards, supporting the customized upgrading of agricultural spraying equipment.