经土壤链霉菌的分离、筛选得到抗稻瘟病的强拮抗菌D-2。对峙培养表明,D-2菌株在PDA平板上对稻瘟病菌、油菜菌核病菌、小麦赤霉病菌和黄瓜枯萎病菌的抑菌率分别为92.2%、78.9%、53.3%和52.2%。根据形态特征、培养特征、细胞壁化学组分分析和生理生化分析,D-2菌株被定名为烬灰吸水链霉菌(Streptomyces cinereohyg roscopicus)。D-2菌株发酵液经乙酸乙酯萃取、浓缩得橙黄色活性粗提物,活性物质在酸性环境下稳定性较差,在中性或偏碱性环境下80℃处理1 h、可见光(4 000 lx)处理12 h、紫外线(2 400 lx)处理4 h活性均保持不变。通过硅胶柱层析和硅胶薄层层析得到了主要的纯活性组分。选择不同的溶剂和乳化剂交叉配制成9种生物农药进行田间小区试验,结果表明:以甲醇作溶剂,吐温80作乳化剂防效最好,达65.69%。 Streptomyces soil separation, screening to obtain a strong antagonistic bacterial blast resistant D-2. The confrontation culture showed that the antibacterial activity of D-2 strain on PDA strain was 92.2%, 78.9%, 53.3% and 52.2% against Magnaporthe grisea, Sclerotinia sclerotiorum, Fusarium graminearum and Fusarium oxysporum f. The D-2 strain was named Streptomyces cinereohyg roscopicus according to its morphological characteristics, culture characteristics, cell wall chemical composition analysis and physiological and biochemical analysis. The fermentation broth of D-2 strain was extracted with ethyl acetate and concentrated to give an orange-yellow active crude extract. The active substance was less stable in acidic environment and was treated under the neutral or alkaline conditions at 80 ℃ for 1 h. Visible light (4 000 lx) for 12 h, and the UV activity (2,400 lx) for 4 h remained unchanged. The main pure components were obtained by silica gel column chromatography and silica gel thin layer chromatography. Choose different solvents and emulsifiers cross preparation of nine kinds of biological pesticides field trials, the results showed that: methanol as a solvent, Tween 80 as the best emulsifier, up to 65.69%.