Research progress on bouncing behavior and control technology of pesticide droplets at plant leaf surface

To control agricultural pests using pesticide, it need to deposited on the target interface effectively. The deposition of pesticide droplets on the target plant leaves is a complex dynamic process, which can be affected by the micro structure and component characteristics of the plant leaves. The leaves of plants with hydrophilic villi or amorphous waxy usually have good wettability, and the droplets are not easy to bounce and roll off. However, the surface of most plant leaves is covered with cuticular waxy layer, which has epidermal cell protrusion or unique micro-nano structure. Therefore, those leaves are difficult to be wetted, which will lead to pesticide droplets bouncing and fragmentation after it hits the target plant leaves. Statistic data demonstrated that, on average, 20%-30% of the pesticide droplets were lost due to rebound and left in the ecological environment, which was the key factor affecting the effective utilization rate of pesticides. In this paper, the bouncing behavior of droplets on smooth solid surface, rough interface after artificial modification and leaf surface of target plant has been reviewed. The key factors influencing the bouncing behavior of droplets on solid surface have been summarized, and the research progress on how to control the bouncing behavior of pesticide droplets on the solid surface was summarized, which will provide new ideas and directions for improving the target deposition rate and the pesticide utilization rate.