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

BACKGROUND: 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. RESULTS: 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. CONCLUSION: 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.