In order to investigate the effect of using plant protection unmanned aircraft on the canopy droplet deposition distribution of Jinggang honeydew fruit trees, this paper used DJI-T50 as the carrier for the application test, and different combinations of operational parameters were optimized by comparing the droplet deposition distribution of each group of tests under the selection of different flight speeds, relative canopy heights, droplet particle sizes, and additive types. Then, three different flight paths were compared based on the optimal parameter combinations obtained. Finally, based on the screening of the optimal operation mode and operation parameter combinations, a Panonychus citri fly control test was carried out on the fruit trees of Jinggang honeydew, and the reduction of P. citri infestation under the operation of four different agents was investigated. The results showed that when the relative canopy height was 3 m, the flight speed was 3 m/s, the droplet size was 210 μm, the additive was Weizhijian, and the operation mode was fixed-point rotary operation, the effect of droplet deposition by plant protection unmanned aerial vehicles (UAVs) was better; in the control of P. citri, the effect of avibenzoxazole suspension was better, and it could reach 88.34% on the 7^th day after the application of the drug, while the effect of acetazolamide suspension was faster. The water emulsion of lufenuron caused a surge of P. citri population in the early stage, and then decreased slowly. The conclusions of this paper can provide data support for the fly-control operation of Jinggang honeydew, and provide theoretical basis for improving the control effect of P. citri in Jinggang honeydew.

To enhance adaptability in orchards with taller average tree heights and improve spraying effectiveness on Jinggang pomelo trees, this paper proposes a UAV-UGV cooperative targeted spraying system (UCTSS) and develops a prototype. The UCTSS primarily consists of a UAV and a UGV, networked using the Robot Operating System (ROS). During operation, both the UAV and UGV navigate between tree rows while carrying the spraying module. When the UAV reaches suitable spraying positions, the UGV halts to activate the spraying module, and the UAV performs targeted spraying from top to bottom. The paper employs a master-slave method for basic formation control of the UAV and UGV, resulting in an average tracking error of 0.118 m and a standard deviation of 0.040 m during testing. Additionally, a LiDAR-based targeted spraying detection method is designed and validated through simulation experiments, achieving an accuracy rate of 96% with an average position error of 0.13 m. Field trials in orchards demonstrate that the UCTSS meets stability requirements, with the average tracking error of the UAV measuring 0.158 m during coordinated movement and 0.013 m during spraying. In terms of spraying effectiv eness, the UCTSS exhibits higher average droplet density and deposition values at various heights of the same tree compared to the DJI-T50, along with a lower coefficient of variation between levels, resulting in a more uniform spraying effect. The feasibility of the UCTSS is validated, providing a novel approach for orchard protection in areas with taller average tree heights.