Chemical Control of Garlic Leaf Blight Through Unmanned Aerial Vehicle Based Application

Fungicides have been a reliable and efficient option for controlling various fungal plant pathogens, and unmanned aerial vehicle (UAV) systems have improved the cost and labor efficiency of fungicide application. However, UAV-mediated disease control systems still have the potential to improve application efficiency and control efficacy. In this study, we evaluated the in vitro sensitivity of garlic leaf blight pathogens (Stemphylium spp.) to different fungicides and performed pot and field assays using mobile spraying equipment (MSE) and an agricultural UAV to select the appropriate fungicide and concentration for controlling garlic leaf blight. Recently isolated Stemphylium spp. showed reduced sensitivity to kresoxim-methyl and various sensitivity to boscalid, ipflufenoquin, mancozeb, and metconazole. In the pot assay using the MSE, metconazole and ipflufenoquin were the most effective among the five ficacy, respectively. Further concentration experiments showed high control efficacy of metconazole and ipflufenoquin at the labeled concentration, indicating that the MSE successfully simulated UAV spraying conditions. Under field conditions, UAV-mediated fungicide application showed higher control efficacy (45.54%) and a lower mean AUDPC value for metconazole at the labeled concentration. Consistent fungicide application was verified by calculating the surface coverage area of water-sensitive papers after application by the MSE or UAV. This study provides a basis for developing a more efficient and effective UAV-based fungicide application system.