Isolating, Screening And Identification Of Biocontrol Actinomyces

The actinomyces having strong biocontrol potential capability were obtained in this study. The biological characteristic and inhibiting effect in greenhouse of these were studied.By the diluting and trapping methods, seventy-three strains of actinomycetes were isolated from the soil samples collected from Qianxian country, Shaanxi province and Weifang, Shandong province.By antagonism in Petri dish and shake-flask fermentation trials, four actinomyces having strong biocontrol potential capability were screened, named SW6,SW9, SW16, SW20, respectively. Strain SW20 has the strongest biocontrol potential capability, while the disease index of the control done with water arrived 96.42, the efficiency of control was 81.48%. All of these isolates were sensitive to antibiotic.Which have high resistance to several fungicides, such as 50% procymidone, 18% triadimefon and 70% thiophanate-methy.The four isolates could not colonized in the body of plant, but could be found in rhizospher. These could promoted the development of embryo of cucumber and tomato and radicel of tomato, different concentration of those have different effect.Those affected tomato in different part. SW20 had the greatest effect on the height and dry weight of plant. Root vigor of plants treated by strain SW6 was stronger than the control during the whole growth period of plant and ratio of root to shoot of plants increased 24.1% than control.Strain SW20 was identified as Streptomyces flaveus based on morphology, characteristic of culture, characteristic of physiology, biochemistry and the system development of 16S rDNA.