Studies On The Antimicrobial Synergism And Preparation Of Bamboo Extract With Kresoxim-methyl

In this paper, by orthogonal experimental design, the best condition for extraction of bamboo leaves was established, and the antifungal synergism of bamboo extract with kresoxim-methy to Gibberella sanbinetti was studied in the laboratory. The preparations of bamboo extract and the combination with kresoxim-methy were developed. The field control efficiencies of the selected preparations to pepper gray mold were evaluated. The main results were following:1.95% ethanol was taken as extraction solvent, and a 20L multi-function extraction and enrichment unit was used as test equipment.The orthogonfl design were used to optimum for the best condition for extraction of bamboo leaves. The best extraction conditions was 70 ℃ as extracting temperature,1.5 hours per time, two times of extraction and 1:25（W/V） of material and alcohol ratio. Under this condition, the extraction of bamboo extract optimal.2.The BE EW was developed using selection of solvents, emulsifiers and other additives.The formulations were:10% bamboo extact,10% emulsifiers,20% solvent,4% antifreeze N,0.2% thickener M, adding water to 100%. The experiments of thermal storage, cold storage, melt-freeze, the stability experiments and persistent foaming of BE EW were developed, and the results showed that there had no phenomenon of hierarchical agent, sedimentation, water separating performance and a small amount of oil separating. The characters of BE EW were in accordance with the quality sandards of EW preparation.3. The antifungal synergism of bamboo extract with kresoxim-methy to Gibberella sanbinetti Miura was studied in the laboratory. The results showed that the EC₅₀ values of the mixtures with the ratios of 5:1,7:1,9:1,15:1,49:1 and 99:1 （bamboo extract: kresoxim-methyl） were 2.37×10-2,2.56×10-2,2.25×10-2,3.20×10-2,23.20×10-2,191.3×10-2, respectively, which were lower than the EC₅₀ value of the bamboo extract （1.20 × 103mg/L）, and higher than the EC₅₀ value of kresoxim-methyl （0.28×10-2mg/L）. The co-efficients of the mixtures were 70.88,87.5,124.4,139.95,26.64 and 14.63, respectively. The mixtures with the ratio of 9:1 and 15:1 （bamboo extract:kresoxim-methyl） have significantly antifungal synergism effects.4. The bamboo extract·kresoxim-methyl EW was developed using selection of solvents,emulsifiers and other additives.The formulations were:10% bamboo extact,0.7% kresoxim-methyl,10% emulsifiers,20% solvent,4% antifreeze Q,0.2% thickener P, adding water to 100%. The experiments of thermal storage, cold storage, melt-freeze, the stability experiments and persistent foaming of bamboo extract’kresoxim-methyl EW were developed, and the results showed that there had no phenomenon of hierarchical agent, s edimentation, water separating performance and a small amount of oil separating. The characters of bamboo extract·kresoxim-methyl EW were in accordance with the quality sandards of EW preparation.5. The field trials of 10% bamboo extract water emulsions and 10.7% bamboo extract ·kresoxim-methyl complex aqueous emulsion were performed to evaluate the control effects on pepper gray mold. The results showed that different treatments had control efficiency to chili mould, the effect increased along with the increased concentration. The doses of 10% bamboo extract water emulsions were desighed as 200ml/acre,400ml/acre and 600ml/acre respectively, and the control efficiencies were 59.9%,65.9% and 68.6% in 7d after the first application, which were lower than the control effectiencies in 7d after the second application （The control efficiencies were 76.8%,80.1%,86.5%）. The doses of 10.7% bamboo extract ·kresoxim-methyl water emulsion were desighed as 10ml/acre, 20ml/acre and 30ml/acre respectivcly, and the control efficiencies were 58.2%,67.8% and 71.2% in 7d after the first application, which were lower than the control effectiencies in 7d after the second application. The control efficiency of 10.7% bamboo extract ·kresoxim-methyl water emulsion in the concentration of 30ml/acre was 88.1% in 7d after the second application, which was higher than the control efficiency of 10% bamboo extract water emulsion in the concentration of 600ml/acre （86.5%）, and similar with the control efficiency of 0.3% matrine botanical pesticide in the concentration of 200ml/acre （89.6%）.