| The bioinsecticide had the characteristics of high effect and low toxic to plants, human and environment. Use the bioinsecticide to substitute or partially substitute the chemical pesticide to control the plant diseases should be the expanding direction. The fermentation products of strain S2 which preserved in our lab exhibited strong insecticidal activity. Utilizations and exploitive prospects of strain S2 were summarized, the main research work and its results were as follows:By studying the morphology, 18S rDNA and phylogenetic tree, strain S2 was identified to be most close to the strain M.ramannianus.The insecticidal activity of fermentation extracts were assessed on third instar larvae, compared to serial doses insecticidal activity of two standards and blank control. Intracellular product and extracellular products both showed insecticidal activities against silkworms. Evaluated with LC50, the result revealed that the insecticidal substance was existed mainly in the mycelium.A semi-quantitative method for determing fermentation extracts based on ultraviolet spectrophotometry was established. Based on the UV scanning spectra, correlative analysis showed that there was a positive correlation between insecticidal activities and A254. The results indicate that ultraviolet spectrophotometry was feasible and reliable when applied to the analysis of insecticidal activities.Retention time of insecticidal substance and three control insecticides was not coincide by HPLC method. The TLC method was developed at room temperature using a mixture of hexane-acetone-methano(l7:3:1,V/V/V). It was showed that HPLC method is infeasible in insecticidal substance analysis.The best optimal liquid fermentation condition and medium component was researched as follows: glucose 1%, soluble starch 2%, casein 0.033%, peptone 0.066%, CaCO3 0.05%, and the initial pH 7.2, inoculum age 48-66h, inoculum size 10%, inoculation amount 150 ml(500 ml), fermentation time 6d.
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