Minimizing Occupational Exposure to Pesticide and Increasing Control Efficacy of Pests by Unmanned Aerial Vehicle Application on Cowpea

Pesticide operators are often exposed to high levels of contaminants, leading to potential adverse health impacts on these agricultural workers. In tropical regions, pesticide applicators are more vulnerable to dermal exposure than their counterparts in temperate regions. Thus, it is highly desirable to develop new spraying methods to minimize the pesticide exposure level without sacrificing the pest control efficiency. Due to their flexibility, high efficiency, and lower labor intensity, unmanned aerial vehicles (UAVs) have attracted considerable attention in precision pest management. However, the pesticide operator exposure assessment during the spraying application with UAVs, especially the comparison with conventional ground sprayers, has not been well investigated. In this work, the control effect against thrips on cowpea and operator exposure determination by aerial and ground spraying in Hainan Province were carried out and compared. When biopesticide spinetoram with the same dosage was applied, the field control efficacy against cowpea thrips sprayed by UAVs was higher than that of knapsack electric sprayers. Moreover, UAV spraying could greatly reduce water consumption and working time. For UAV spraying, when the amounts of water applied per hectare were 22.5, 30, and 37.5 L, the control effects on thrips on the first day were about 69.79%, 80.15%, and 80.58%, respectively. When Allura Red as a pesticide surrogate was applied under similar spraying scenarios with the field control against thrips on cowpea, the average total unit exposure of the knapsack operator (1952.02 mg/kg) was greatly higher than that of the UAV operator (134.51 mg/kg). The present research indicates that plant protection UAV is the direction of development of modern intensive sustainable agriculture