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Pest control is essential for increasing agricultural production. Agricultural drones with spraying systems for pest control have generated great interest among farmers. However, spraying systems installed on unmanned aerial vehicles, like any other sprayer, can cause damage to the environment due to drift of the agent. Air induction (AI) nozzles are known to produce less drift (e.g., larger spray drops) than other nozzles, but there is a lack of research analyzing their effectiveness in combination with drones. In this study, AI and flat fan nozzles were installed on drones to evaluate their spray and pest control performance. Aerial spraying was conducted on rice and soybeans to measure the coverage and penetration ratio and analyze the crop production as well as the crop damage due to pests and diseases. The drone flight was conducted at an altitude of 3 m and a velocity of 2 m/s. Spray droplets were collected using water-sensitive paper at two heights above the soil surface. The experiments showed that the crop coverage with the AI nozzle was 130% higher than that with the flat fan nozzle. The drift reduction of AI nozzles increased the coverage of spray droplets. But the difference in the penetration ratios, which is the ratio of agents to be delivered inside the crop, was not significant between the nozzles. Also, there was no significant difference in crop yield and pest control efficacy. Consequently, the performance of the AI nozzle did not show differences from that of the XR nozzle, except for coverage. However, the AI nozzle raised less drift, so it should be considered for use in aerial control. [ABSTRACT FROM AUTHOR]

The use of unmanned aerial spray systems (UASS) has increased owing to their many advantages. However, studies related to a standardized method to evaluate the spray performance of UASS are lacking. Therefore, in the present study, a quantitative analytical method using a food dye tracer was compared with the image analysis method, and the effects of experimental conditions on spray deposition were assessed. Concordance between the results of quantitative and image analyses was examined. The coverage of water-sensitive paper (WSP) and Medley Velvet (MV) was compared using image analysis. Moreover, the effects of flight altitude and collector height on spray deposition amount and effective spray width were evaluated. The results showed a significant correlation between the deposition and the coverage of MV (R2 = 0.6782, p-level < 0.001). The coverage of MV is different from that of WSP. In addition, the correlation coefficient between the coverage of WSP and that of MV was smaller than the correlation coefficient between depositions and the coverage of MV. Therefore, MV should be used instead of WSP for more accurate analysis. The lower the collector height, the smaller the deposition amount. The effective spray width increased as the distance between the collector and UASS increased, whereas the total deposition amount decreased when the collector was close to the ground. Overall, using a food dye tracer, both quantitative and qualitative analyses can be applied simultaneously, and this method may replace analysis using WSP. [ABSTRACT FROM AUTHOR]