## Abstract
In the aspect of deposition uniformity, a multi-spraying swath test is conducted with different UAV sprayers [9]. There is an obviously inconsistent amount of deposition in the longitudinal and lateral direction and this phenomenon has been reported in many studies [7; 10; 11]. The control efficacy on pests and diseases is one of the most important evaluation indices of chemical application. Quite different from the conventional large volume application, the UAV sprayer belongs to low volume (LV, 4.7-46.7 L/ha) or ultra-low volume (ULV, 0-4.7 L/ha) [12] spraying equipment with the spray volume in the range of 1-40 L/ha [6; 11]. Meanwhile, with the same active ingredient applied per acre, the chemical concentration of UAV is particularly high. [PERSON] et al. [7] studied the control efficacy of HyB-15L UAV with spraying Chlorpyrifos-Regent EC against plant hoppers and found that the insecticidal efficacy is 92% and 74% at 3 and 10 days after application, respectively. On the premise of guaranteed control efficacy, the working efficiency is another important evaluation index of application. Currently, UAVs mostly rely on semi-autonomous control with the flight altitude belonging to autonomous control. The control range is 200-300 m in visible distance with manual control [6]. The payload capacity of the aerial application UAVs is generally 5-25 kg [6; 13; 14]. Considering the limited payload and the flight range, the effective spray work rates of 2-5 ha/h can be achieved in a vineyard with a gasoline-powered helicopter (RMAX, Yamaha motor Co., Cypress, CA, USA) [11]. The working efficiency of different UAVs in the grain-filling stage of wheat was studied by [PERSON] et al. [9], with the daily working area ranging from 13.4 to 18.0 ha in 8 h. Pesticide spray drift is an important environmental problem for aerial application. Compared with the manned agricultural aircraft [6; 15; 16], the droplet drift of UAV is effectively reduced with the lower flight height [6; 7] and the downwash wind [17; 18]. According to [PERSON] et al. [19], under the wind speed of 3 m/s, 90% of drift droplets of Z-3 UAV are located within a range of 8 m of the target area. Similar to [PERSON] et al., [PERSON] et al. [17] measured that 90% of drift droplets of a fuel powered single-rotor UAV are within 9.3-14.5 m under the wind speed of 0.76-5.5 m/s. Compared with the conventional boom sprayer [20; 21], the droplets drift distance of UAV sprayer would be further. Despite these preceding studies, research is focused mainly on parameter optimization, droplet deposition and biological efficacy of one equipment. Few studies compare different kinds of crop protection equipment, especially including UAV sprayer. Under the same working condition, the comparison of different crop protection equipment on deposition, control efficacy and working efficiency is very important for equipment selection and application quality analysis. The main objective of this research was to compare the application quality of a battery motive 3 WTXC8-5 six-rotor UAV with a 3 WX-280H self-propelled boom sprayer and two conventional knapsack sprayers (3 WBS-16A2 electric air-pressure knapsack sprayer and WFB-18 knapsack mist-blower sprayer). The comparison items included the spray deposition on the plants and run-off, uniformity and penetrability of the deposition, deposition characterization (including droplet size, number of spray deposits and the area of coverage), pesticide efficacy on wheat aphid and working efficiency. The experimental results show that the control efficacy of the UAV on wheat aphid was comparable to other spraying equipment with the working efficiency significantly higher than others. Unfortunately, UAV still have many problems on deposition uniformity and droplets penetrability.