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

Area of Science:

• Agricultural Engineering
• Precision Agriculture
• Environmental Science

Background:

• Orchard pest management increasingly utilizes unmanned aerial vehicles (UAVs) for efficiency and environmental benefits.
• UAVs offer advantages in complex terrains but struggle with consistent spray deposition and drift control.

Purpose of the Study:

• To review recent advancements in UAV spraying technology for orchard systems.
• To identify key factors limiting spray effectiveness and environmental risks.
• To outline future research directions for next-generation UAV spraying.

Main Methods:

• Systematic review of UAV spraying mechanisms, performance, technology, and applications.
• Analysis of aerodynamic airflow, droplet transport, and canopy penetration.
• Integration of findings across diverse crops and environments.

Main Results:

• Spray efficacy is limited by insufficient inner-canopy deposition due to airflow and canopy resistance.
• Technological developments (nozzles, droplet size, adjuvants, flight strategies) improve deposition and reduce drift.
• Emerging technologies enable targeted spraying based on pest distribution.

Conclusions:

• Understanding spray physics is crucial for optimizing UAV pest suppression and environmental safety.
• Addressing technical bottlenecks will advance UAV-enabled sustainable orchard pest management.
• This review provides a structured framework for future research and development.