| Controlling agricultural pests is an important guarantee for agricultural economy, even for the development of national economic. But the current machines for plant protection are difficult to meet the needs of controlling crops pests efficiently. Therefore, it has great significance of developing plant protection machineries and efficient drug-delivery technology. Poor intermiscibility with commodity pesticides, and serious environment pollution constrain thermal fogger to be applied in controlling crops pests, although it is more efficient and higher control effect. Based on the thermal fog stabilize applied in highstalk crops, a new thermal fog stabilizer which has better settling effect, less affect by meteorological factors and is suitable for middle and low stalk crops, was development in this paper. First, find out surfactants which make the oil of condensation nuclei material suspension stability by single substance screening. Then, test the stability at heat storage and cold storage, intermiscibility with commodity pesticides, and distribution of thermal fog droplets on crop leaves in different horizontal distance. Last, optimizing thermal fog stabilizer step by step, and use the optimized thermal fog stabilizer to control plant diseases and insect pests in the field. The main results are as follows.1. Stability of the mixed system with 7 kinds of condensation nuclei and 13 kinds of solvent, the result shows that the mixed system of solvent oil and HI-1 RQ is stable. It has good emulsifying property at the ratio of 4:6 of nonionic surfactant TX-10 to anionic surfactant TX-10. Thermal fog stabilizer composed by 3%HI-1RQ and 14% emulsifier is better in stability, dispersion, liquidity, and intermiscibility with commodity pesticides.2. When being sure 3%HI-1RQ and 14% emulsifier,proceeding the heat storage and the cold storage stability test and test intermiscibility by different dosage form of commodity pesticide commodity pesticide formulations are mostly EC, SC and SL, thermal fog stabilizer, commodity pesticides, water percentage is 1:3:6, test the stability of the hybrid system,then optimized the compound proportion step by step.3. The number of thermal fog droplets declines gradually with the distance from 0-35m in the wheat feild. With othermal fog stabilizer, the fluorescence points on front leaves is 30-50 per square centimetre, fluorescence points on the back is 20-40 per square centimetre at the distance of 25 meters, which is higher than that of mist sprayer machine. But the fluorescence points with othermal fog stabilizer are less than that of mist sprayer machine at the distance of 30 meters..So the effective control distance with thermal fog stabilize and thermal fogger is 25 m.4. After applying pesticides, measured the contant of carbendazim and triadimefon in the upper leaves, lower leaves, and surface soil by high performance liquid chromatography (HPLC). The contant of carbendazim in the upper, lower leaves and soil is 19.3824mg/L,3.6524mg/L, and 0.8521 mg/L respectively by the mist sprayer; The contant of carbendazim is 12.5457mg/L,8.4161mg/L,0.1131mg/L by the thermal fogger. The contant of triadimefon on the upper, lower leaves and pesticides deposition respectively is 10.317mg/L,3.553mg/L by the mist sprayer, and the contant of triadimefon is 9.085mg/L,8.268mg/L by the thermal fogger. The contant of carbendazim is almost distributed in the upper and lower leaves under the thermal fogge. But it is balanced in the upper and lower leaves by the thermal fogger. The percentage of pesticides deposited in soil sprayed by mist sprayer and thermal fogger is 1.41% and 10.65%, respectively5. Diameter 3.2 mm of nozzle is optimal for 6HYR-36W matched with thermal fog stabilizer by fog droplets numbers distributed in different horizontal distance on leaves with same ingredients and the content of each component.6. Sprayed by the thermal fogger with thermal fog stabilizer, the controlling efficiency of one time is 74.7% on wheat head scab, two times is 87.4%. Sprayed by the mist sprayer, the control efficiency of one time is 68.4%, two times is 85.2%. Controlling efficiency on wheat powdery mildew and wheat aphid by the thermal fogger is 80.0% and 95.4%, respectively. These are 77.2% and 92.1% by the mist sprayer, respectively. |
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