UAV-based spraying in orchard systems: mechanisms, performance indicators, and integrated applications

The increasing demand for precise, efficient, and environmentally responsible pest management in orchards has accelerated the adoption of unmanned aerial vehicle (UAV)-based spraying systems. Compared with conventional ground-based or manned aerial applications, UAVs offer superior adaptability to complex canopies and fragmented terrain. However, inconsistent canopy deposition, limited penetration into inner canopy layers, and drift-related environmental risks continue to constrain their pest control performance.

This review synthesizes recent advances in UAV spraying for orchard systems through an integrated mechanisms-performance-technology-applications framework. By systematically analyzing aerodynamic airflow structures, droplet transport behavior, and canopy accessibility, we identify consistent cross-system patterns governing spray effectiveness. Evidence across crops and environments shows that pest control efficacy is primarily limited by insufficient inner-canopy and abaxial deposition, driven by heterogeneous rotor-induced airflow and canopy resistance. Recent developments in nozzle design, droplet size regulation, adjuvant use, and adaptive flight strategies have partially mitigated these limitations, improving deposition uniformity while reducing off-target drift and operator exposure. Emerging perception-driven and variable-rate spraying technologies further enable spatially targeted applications aligned with pest distribution.

By linking spray physics to pest suppression outcomes and environmental safety, this review clarifies the technical bottlenecks and priority research directions for next-generation UAV spraying systems. The findings provide a structured basis for advancing UAV-enabled, sustainable pest management in orchard ecosystems. © 2026 Society of Chemical Industry.