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【目的】生物农药安全无害,环境友好。为了评价寡雄腐霉发酵液(Pythium oligandrum broth,POB)的动物安全性和防病促生效应,研制高效、无害的生物农药。【方法】试验利用自主分离的寡雄腐霉生防菌株(P.oligandrum CQ2010)制备POB,通过动物试验、拮抗试验、盆栽和生产试验,研究了POB的动物毒性,对黄瓜蔓枯病的防治作用,以及对黄瓜生长、产量和品质的影响。【结果】用大剂量的POB灌胃给药对小鼠体重增长无显著影响,其外观和行为均无异常,组织器官也未见病理改变。POB对甜瓜球腔菌的抑制率为51.95%,药效介于1∶800的百菌清溶液和1∶200的甲基托布津溶液之间。在黄瓜幼苗接种甜瓜球腔菌前后喷施POB,叶片丙二醛含量下降,过氧化物酶和超氧化物歧化酶活性增强,发病率和病情指数均显著降低,相对防治效果达到54.8%–64.1%,故POB能减轻病原菌对细胞膜的伤害,激发防御性生理反应,增强黄瓜植株的抗病能力。此外,POB处理提高叶绿素含量,增强根系活力,增加植株氮、磷、钾吸收量,促进黄瓜植株生长,生物量和果实产量分别提高81.10%和11.58%。POB还使黄瓜果实Vc和可溶性糖提高,硝酸盐含量降低。【结论】寡雄腐霉发酵液对动物安全无毒,能有效防治黄瓜蔓枯病,促进黄瓜生长,提高产量品质。
【Objective】 Biopesticides are safe, environment-friendly. In order to evaluate the animal safety and disease-prevention and growth-promoting effects of Pythium oligandrum broth (POB), an efficient and harmless bio-pesticide was developed. 【Method】 POBs were prepared from P. oligandrum CQ2010, which was autonomously isolated. The animal toxicity, the pot experiment and the pot experiment were conducted to study the animal toxicity of POB and the control of cucumber viper's disease Effect, as well as on cucumber growth, yield and quality. 【Results】 The intragastric administration of large doses of POB had no significant effect on body weight gain in mice. The appearance and behavior of the mice were normal and no pathological changes were found in tissues and organs. The inhibitory rate of POB to the muskmelon is 51.95%, the effect is between 1: 800 and the ratio of chlorothalonil solution is 1: 200. POB was sprayed before and after cucumber melon inoculated with M. meliloti, the content of malondialdehyde in leaves decreased, the activity of peroxidase and superoxide dismutase increased, the morbidity and disease index decreased significantly, the relative control effect reached 54.8% -64.1 %, So POB can reduce the damage of pathogenic bacteria on the cell membrane, stimulate defensive physiological responses and enhance the resistance of cucumber plants. In addition, POB treatment increased the content of chlorophyll, increased root vitality, increased the uptake of nitrogen, phosphorus and potassium, and promoted the growth, biomass and fruit yield of cucumber by 81.10% and 11.58% respectively. POB also increased the Vc and soluble sugars in cucumber fruits and decreased the nitrate content. 【Conclusion】 Pythium oligosaccharides fermentation broth is safe and safe to animals, it can effectively prevent cucumber leaf blight, promote the growth of cucumber, and improve the yield and quality.