Effects of dose and distribution of pesticide droplets on pests control efficiency and its relationship with pesticide losses

In order to clarify the action mode of pesticide droplet in dose transfer, the interaction patter of pesticide dose, its distribution in the process of crop protection and pest control, and pesticide loss during the process were summarized. When the dose of pesticide was defined, pesticide droplets, which were the carrier of pesticide, landed on the surface of rice and formed the deposit. The pest would be killed after the lethal dose was obtained. The pest was very easy to contact with the pesticide dose when the droplets were succession and uniform distribution. If the pest obtained the lethal dose in the first time, the pest would die and other doses were wasted. If the lethal dose was not obtained at the first time, the pest would continue to harm the leaf until a lethal dose was obtained. When the loss point of the leaf was exceeded, the deposition amount would be reduced by approximately 50% and the dose would be lost. The more application rate was increased, the more dose would be lost. Compared to the situation where no pesticide was lost, more than twice of the pesticide dose was needed to ensure that the lethal dose was obtained. When the deposit on the leaf surface was discrete: ① If the deposit was appropriate size and contained a lethal dose, the pest would die after the contact with the deposit. However, if the number of the deposit was not enough, and the pests would continuous harm the leaf until the lethal dose was obtained. ② If the deposit was too small and did not contain a lethal dose, the pest would continue to harm the leaf until the lethal dose was obtained. ③ If the deposit was too large and contained a lethal dose, the pest could only contact a small portion of the deposit and could not obtain the lethal dose. The pest would continue to harm within the range of the deposit, or in the gaps between several deposits until the lethal dose was obtained. ④ If the deposit contained a dose beyond lethal requirement, the pest would die after the contact with the deposit. However, part of the excess dose was wasted. In a conclusion, plenty of pesticide deposits were necessary in order to kill pests and protect crops. The number, size and dosage of the deposit on a unit area constitute the pesticide deposition structure. Different deposition will result in different biological effect and it is relation to the pesticide utilization efficiency.