## 3 Results and Analysis
### Plasma Degradation Effect of Five Acaricides on the Surface of Kumquats
As shown in the figure, the degradation rate of spiromesifen generally increases with increasing discharge voltage. When the voltage is 20 kV, discharge phenomena are significant, and the degradation rate is 62.4% after plasma treatment for 20 min. However, the degradation rate at 10 kV is almost the same as that at 0 kV. The main reason for this phenomenon may be that after the active substances in the plasma decompose spiromesifen into smaller molecules, the presence of these smaller molecules in the solution inhibits the further degradation of larger molecules. When the discharge voltage is 15 kV or 20 kV, the degradation rate of spiromesifen increases with the increase in treatment time. When the discharge voltage is 20 kV, the degradation rate of spiromesifen is 44.17% after 10 min of treatment and 62.40% after 20 min of treatment. This is because with the increase in processing time, there is a greater presence of active substances in the plasma, resulting in a higher degradation rate of spiromesifen. When the discharge voltage is 0 kV or 10 kV, the degradation rate after 20 min of treatment is lower than that after 15 min of treatment, as explained in the previous paragraph. The effects of voltage and processing time on the degradation of etoxazole are shown in Figure 3D. The results of the variance analysis indicate that both discharge voltage and processing time have a significant effect on the degradation rate of etoxazole (\(p<0.05\)). As can be seen from the figure, the degradation rate of etoxazole increases with increasing discharge voltage. When the voltage is 20 kV, significant discharge phenomena occur, and after plasma treatment for 20 min, the degradation rate reaches 62.4%. However, when the processing time is 10 min or 15 min, the residual amount of etoxazole at 0 kV discharge voltage is smaller than that at 10 kV discharge voltage. The main reason for this phenomenon may be that when the discharge voltage is 0 kV, etoxazole is mainly dissolved in water, resulting in a decrease in the residual amount. When the discharge voltage is 10 kV, a small amount of active substance is produced, which attacks some etoxazole molecules, causing them to decompose into small molecules. The increase in the concentration of small molecules in the solution then inhibits the degradation of large molecules, leading to this phenomenon. The degradation rate of etoxazole increases with the increase in treatment time. When the discharge voltage is 20 kV and the treatment time is 10 min, the degradation rate of etoxazole is 21.84%. When the treatment time is increased to 20 min, the degradation rate increases to 48.93%. This is because with the increase in treatment time, there is a greater presence of active substances in the plasma, which leads to an increase in the degradation rate of etoxazole. However, when the discharge voltage is 0 kV or 10 kV, the degradation rate after 20 min of treatment is lower than that after 15 min of treatment, as explained in the previous paragraph. The effects of discharge voltage and treatment time on the degradation of lufenuron are shown in Figure 3E. The results of the variance analysis indicate that both discharge voltage and treatment time have significant effects on the degradation rate of lufenuron (\(p<0.05\)). As can be seen from Figure, the degradation rate of lufenuron generally increases with increasing discharge voltage. When the treatment time is 20 min and the discharge voltage is 15 kV, the degradation rate of lufenuron is higher than that when the discharge voltage is 20 kV. The main reason for this may be that when the discharge voltage is 20 kV, there are more active substances in the plasma, and the speed of decomposition of small molecules produced by the degradation of lufenuron is faster, which in turn inhibits the degradation of large molecules of lufenuron, resulting in this situation. The degradation rate of lufenuron increases with the increase in treatment time.