Study On The Control Effect And Promote Growth Of Nonpathogenic Fusarium Oxysporum FO47 And FO47B10 On Watermelon And Cucumber

The safety to the 8 common crops and the colonizing ablitity in 6 crops of nonpathogenic Fusarium oxysporum strain FO47 and strain FO47B10 were investigated in laboratory and field. The control effects to diseases were determined using seedling of cucumber, watermelon, muskmelon and cotton inoculated with conidia of FO47 and FO47B10 in the soil in advance, and the enzyme activity of plant root were tested after inoculated with the strains in cucumber.The results indicate that the strain FO47 and FO47B10 were safe for common crops including wheat, corn, cotton, tomato, pepper, watermelon, cucumber and soybean, and the 6 common crops could be colonized with 2 strains. In the most of tested crops, the colonizing ability of strain FO47B10 was better than strain FO47.Two strains had different tolerance to the eight tested fungicides commonly used in greenhouse, including mancozeb, mildothane, matalaxyl, chlorothalonil, carbendazim, procymidone, triadimefon and quintozene.No antagonistic effect were found on PDA plates between the FO47 and FO47B10 with F. oxysporum f.sp. cucumerinum, F. oxysporum f.sp. niveum , F. oxysporum f.sp. vasinfectum and V. dahliae. The growth rate of strain FO47 was faster than strain FO47.Inoculating FO47 and FO47B10 in the soil in advance, the control efficacy of FO47 on F. oxysporum f.sp. cucumerinum, F. oxysporum f.sp. vasinfectum and Pseudoperonospora cubensis was more effective than on Sphaerotheca fuliginea. The effective control effects could be obtaind with FO47B10 against F. oxysporum f.sp. cucumerinum, F. oxysporum f.sp. vasinfectum, Pseudoperonospora cubensis and Sphaerotheca fuliginea. The control efficacy of FO47 and FO47B10 to the diseases were declined in the process of time. Verticillium dahliae could be effectively controlled with FO47 and FO47B10 in the cotton variety 99B.The growth of cucumber and watermelon plant were promoted inoculating strain FO47 and FO47B10 in the soil in advance, the tolerance of plants to the low temperature could be enhanced, and the quality of watermelon were improved. Strain FO47B10 was better than strain FO47 in the efficacy. The content of gibberellin produced by the strain FO47B10 was higher than that of the strain FO47.