| Tetranychus piercei McGregor belongs to class of Arachnida, subclass of Acari, family of Tetranychidae, and genus of Tetranychus, and it is against a variety of crops, such as bananas, papayas and other fruit trees and some vegetable crops. It is often the dominant species especially in the banana growing areas during the high temperature in summer and on the drought areas. As an important means of prevention and control of Tetranychus piercei McGregor, chemical control seems very inadequate now. On the one hand, the mite produces resistance easily to the commonly insecticides and acaricides, while the pharmacy with good control efficacy is high-toxic and pollution. On the other hand, the research on application technology of pharmacy using to control Tetranychus piercei McGregor is also very weak.Accordingly,15 kinds of original pharmaceutical drugs of insecticides and acaricides were made as the main screen in this thesis. We detected the LC50 of 15 insecticides and acaricides to the female Tetranychus piercei McGregor in Key Laboratory of Pests Detection and Control for Tropical Agriculture of Hainan Province. On the basis of interior bioassay and the optimal ratio of chlorpyrifos and spirodiclofen, which showed the synergistic effect, we formulated its environmental formulation-micromlsion. The main research methods and results could be summarized as follows.1.15 kinds of new promotional and traditional insecticides and acaricides were tested in terms of toxicity to Tetranychus piercei McGrego by means of slide glass immersion. It showed that:abamectin>rotenote> fenpyroximate>pyridaben> chlor-pyrifos>phoxim>Highchlorobenzene>bifenthrin>cyhalothrin>spirodiclofen>fenpropa thrin>profenofos>ddv>propargite>imidacloprid. Chlorpyrifos, phoxim, pyridaben and fenpyroximate had rapid toxic effect and could be used for the controlling of Tetranychus piercei McGrego when the mite was on the full incidence period2. The optimal ratio for mixtures of 6 insecticides in abamectin, chlorpyrifos, phoxim and spirodiclofen were determined in terms of individual insecticide LC50. The results showed that abamectin and phoxim, chlorpyrifos and spirodiclofen are highly synergistic effect in the given proportions. The most synergistic optimal ratio between abamectin and phoxim was 1:18, chlorpyrifos and spirodiclofen was 7:3, respectively.3. According to the physical-chemical characters and synergistic effect of two insecticides chlorpyrifos and spirodiclofen, we formulate microemulsion of chlorpyrifos and spirodiclofen. In addition, we put forward the quality analysis content of the microemulsion of 10% chlorpyrifos-spirodiclofen ME.The result of the adjuvant selecting showed that the better formula of 10% chlorpyrifos-spirodiclofen ME is following. Chlorpyrifos 7% Spirodiclofen 3% Solvent 15% Emulsifier 20% n-Butanol 3% glycol 2% Water add to 100%The quality analysis content of 10% chlorpyrifos-spirodiclofen ME are following. Appearance the clear yellow liquid Chlorpyrifos 7% (mass fraction, same as follows.) Spirodiclofen 3% PH value 5-7 emulsion stability(diluted 200X) acceptable the clear range of temperature(℃)-5-60℃Stability after cold stockpile acceptable Stability after warm stockpile acceptable4. According to the modified pesticide effect test method, controlling effect test of 10% chlorpyrifos-spirodiclofen ME sample against Tetranychus piercei McGregor were carried out in the field. The results indicated that Controlling test for Tetranychus piercei McGreg or indicated that at 100mg/kg(1000X)concentration of the compound, the control effect to adult mite amounted to over 80% within 7 days after treatment. These suggested that the mixed ME of 10% abamectin fenpropathrin had a good control of the population development of Banana. According to the control effect test in the field,we suggest that the applying concentration in the fiele of the compound should be 100mg/kg (1000X).
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