Study On The Control Effects Of Several Biocontrol Actinomyces Strains Againest Fusarium Wilt And Verticillium Wilt

The research took10strains biocontrol actinomyces which were isolated and screenedfrom different environments for years as the object, controlling the Fusarium wilt andVerticillium wilt as the final purpose, through testing the antibacterial ability, safety,environment adaptability and resist ability in the greenhouse of the selected10strainsactinomyces, to screen out the strains which have the most obvious and comprehensivebiocontrol characteristics against Fusarium oxysporum and Verticillium dahliae and providetheoretical basis and practical biocontrol resources for the using of biocontrol actinomyces onthe control of the Fusarium wilt and Verticillium wilt.According to flat confrontation method and micro pore diffusion method, the researchtested the antibacterial ability of the selected10strains actinomyces to the3strains pathogens.The results of the inhibiting effects experiment indicated that the selected10strainsactinomyces all had different degree of antibacterial ability to the3strains pathogens. The soilactinomyces strain153, SC11, SE2and plant endogenous actinomyces strain SF6, SG2hadthe strongest antibacterial ability, with the average inhibition rates of mycelium growth wasmore than50%and had a certain degree of persistance. The antibacterial ability of the other5strains biocontrol actinomyces were significantly different. The strain SC11had the strongestantagonistic effects, with the average inhibition rates of mycelium growth was near to80%. Inthe10strains biocontrol actinomyces, only the fermentation filtrate of strain153and SC11had the obvious inhibition to the3strains pathogens which showed that the two strains couldproduce and release some secondary metabolism substance that had bacteriostasis.Selectting the actinomyces strains153, SC11, SE2, SF6and SG2whose averageinhibition rates to3strains pathogens were more than50%, through indoor pot experiment,the research tested the effects of this5strains actinomyces on the germination of plant seedsand the growth of plant seedlings with the purpose to evaluate the security of the actinomycesstrains on the plant growth. The results indicated that the5strains actinomyces did not haveadverse effects on the budding rate and emergence rate of the plant seeds. At the same time, they had obvious stimulative effects on the growth of the roots, stems, leaves of the plants.Generally speaking, the5strains actinomyces were safe on the growth of plants.According to medicated flat method and organization culture method, the research testedthe tolerability of the strains153, SC11, SE2, SF6and SG2to four kinds of microbicides andtheir colonization ability in the rhizosphere and different tissues of five kinds of plants withthe purpose to evaluate the environment adaptability of the actinomyces strains. The resultsindicated that tolerability of the strains SF6was worst which could not grow when theconcentration of microbicides in the environment was higher than50μg/mL; The colonizationability of strain SE2was poor which only can set budding in the rhizosphere that the buddingscope was small and the budding number was little. The other three strains actinomyces hadstronger tolerability and colonization ability at the same time and the ability to adapt theenvironment were strong as a whole.According to the pot experiment, the research tested the resistance of the strains153,SC11and SG2which had strong environment adaptability on the watermelon Fusarium wiltand eggplant Verticillium wilt. The results indicated that, compared with the CK, when theactinomyces strains existed, the disease index of the plants all had different rate decrease,indicating that the three strains has different rate of prevention effects on the two disease. Thecontrol effects of strains SC11on the two diseases was strongest and same as the the controleffects of50%carbendazol; The control effects of strains153was little weaker than50%carbendazol.Through integrating the results we could find that the biocontrol characteristics of strain153and SC11were comprehensive. Both of them had the advantages of preventing effects topathogens, drug-resistant, easier for colonization, safe to the growth of plants and promotingeffect on the plants growth. Therefore, the two strains had a certain of potential to bedeveloped and utilized.