Study On The Development Of Three Kinds Of Pesticide Microemulsion And Their Antifungal Activities Against Rhizoctonia Solani

With water as the continuous phase and there is no or less use of organic solvents in microemulsion, which has some advantages including small particles, good stability, high efficiency, safety and less pollution, etc. It meets the trend of pesticide formulations development, which has great significance on reducing the pollution problems caused by the abundance use of traditional chemical pesticides.In this paper, carbendazim, difenoconazole, propiconazole and triadimefon were the research object, which had better control effect on the Maize Sheath Blight and mainly were emulsion or water dispersible granule-based in the market. Carbendazim microemulsion, difenoconazole and propiconazole compound microemulsion and triadimefon microemulsion were screened in virtue of pseudternary phase diagrams. The phase diagrams were prepared by titration through the filter of auxiliary solvent. Then the optimal microemulsion formulations of screening were detected further. Identified their type respectively, combined with low temperature stability, thermal storage stability, dilution stability, freezing test and transparent temperature zones, which can detect the physical and chemical stability of the product. And their antibacterial avtivities on high pathogenic fungus anastomosis groups AG1-IA of Rhizoctonia solani were tested. The major results were as follows:1. According to its physical and chemical properties, compound solvents were selected for carbendazim, alkyl A and acid A (Since this study has certain intellectual property rights, has not yet published, so significant additives are presented by letters. The following are the same) by volume ratio of 3:2 mixture of carbendazim solubility up to 30g/L, which was 300 times than the current maximum solubility of carbendazim reported.2. The other components of carbendazim microemulsion were screened:emusifier A and emulsifier B according to mass ratio of 4:2 mixed as compound surfactant, alcohol A as co-surfactant. The optimal formulation of carbendazim microemulsion was:oil:SAA: water= 1:3:4, while the SAA phase consisted of the emulsifier A:emulsifier B:Alcohol A= 4:2:3. Sample of this study was not frozen in-18℃and the cloud point was more than 90℃, which had not reported in the study of carbendazim.3. The components of difenoconazole and propiconazole microemulsion were screened: benzene A as solvent, emulsifier A as surfactant, alcohol A as co-surfactant. The optimal formulation of difenoconazole and propiconazole microemulsion was:oil:SAA:water= 1:2:5, in which the SAA consisted of emulsifier A:Alcohol A=3:2, the performance met the equirements of micro-emulsion and the cloud point was 70℃.4. The components of triadimefon microemulsion were screened:benzene B as solvent, emulsifier A as surfactant, alcohol A as co-surfactant. The optimal formulation of triadimefon microemulsion was:oil:SAA:water=4:3:3, in which the SAA consisted of surfatant A:Alcohol A=4:2. The cloud point was 56℃and the sample was not frozen in-18℃, which greatly improved the low temperature stability of triadimefon preparation which was another major innovation of this study.5. In this paper, the effective ingredients in the microemulsions were determined by High Performance Liquid Chromatography (HPLC), the results were as follows: carbendazim 1.19%, difenoconazole and propiconazole 2.61%, triadimefon 0.97%. The contents were lower than most microemulsion products reported currently. Their thermal storage stabilities were tested according to FAO standards, the decomposition rate of the microemulsions were carbendazim 0, difenoconazole-propiconazole 2.7% and triadimefon 2.1% respectively.6. The microemulsions'antifungal activities were tested in laboratory compared with the same kinds of different formulations. The antibacterial effect by the same dosage or content of actives treatment showed that:Different concentration while under the condition of the effective ingredient were approximately the same, the inhibition ratio of carbendazim microemulsion treatment group was higher than the water solution treatment group, the difenoconazole-propiconazole microemulsion and triadimefon microemulsion treatment group were significantly higher inhibitory than the emulsion treatment group. The results above confirmed that three kinds of microemulsion against have better inhibitory effect against Rhizoctonia solani.