The Control Effeciency And The Microbial Flora Analysis Of Minituber Common Scab Biocontrol

Potato common scab is an important disease in potato production, it has become the main obstacle to the minituber production. We found the scab has become more and more serious because of the repeated using of vermiculites in potato seedling production. In this research the antagonistic strain Bacillus subtilis ZWQ-1, Streptomyces roseoflavus Men-myco-93-63, and other factors such as streptomycin, citric acid were used to treatment the vermiculites seedbed in order to check the control effect of each treatment. The main microbial flora, include the fungi, bacteria and actinomyces, were investigated in different vermiculites, in order to explore the disease control method and lay the foundation for the research of prevention mechanism.The control effects showed that the treatment of antagonistic strain ZWQ-1 with streptomycin is 34.33%, ZWQ-1 with citric acid is 56.93%, Streptomyces roseoflavus Men-myco-93-63 with vermiculites(half used and half new) is 49.02%.The statement results of microorganisms(the bacteria, actinomyces and fungi) showed that the total amount is about 0.60×107CFU/g, which included the bacteria(38.49%), actinomyces(60.24%) and fungi(1.27%) in the new vermiculites. The amount of used vermiculites is about 7.31×107 CFU/g, including bacteria(85.95%), actinomyces(13.96%) and fungi(0.10%). The amount of treatment ZWQ-1 plus streptomycin is about 3.52×107 CFU/g, including bacteria(78.05%), actinomyces(21.85%) and fungi(0.09%). The amount of treatment ZWQ-1 plus citric acid is about 8.15×107 CFU/g, including bacteria(80.53%), actinomyces(19.40%) and fungi(0.08%).The amount of treatment Men-myco-93-63 with vermiculites(half used and half new) is about 7.02×107 CFU/g, including bacteria(91.13%), actinomyces(8.83%) and fungi(0.04%).The amount of water control is about 9.19×107 CFU/g, including bacteria(74.13%), actinomyces(25.25%) and fungi(0.62%).All of the microorganisms obtained from vermiculites samples were identified according to the 16 S r DNA sequence(bacteria and actinomycetes) and ITS sequence(Fungi) in this work. The results showed that the new vermiculites have three genus for bacteria group: Achromobacter, Psychrobacter and Proteus, one genus for actinomyces group is actinomycetes, four genus for fungi group: Penicillium, Aspergillus and Talaromyces. Used vermiculites have six genus for bacteria group: Chryseobacterium hispalense, Pseudomonas, Rhizobium, Bacillus, Proteus and Achromobacter, three genus for actinomyces group: Streptomyces, Arthrobacter and Microbacterium, four genus for fungi group: Penicillium, Fusarium, Aspergillus and Cladosporium.The vermiculites samples were collected from different treatments and the microorganisms were identified. The results showed that the treatment 1 have three genus for bacteria group: Chryseobacterium hispalense, Pseudomonas and Bacillus, four genus for actinomyces group: Microbacterium, Kocuria, Streptomyces and Rhodococcus, two genus for fungi group: Penicillium and Fusarium. The treatment 2 have four genus for bacteria group: Chryseobacterium hispalense, Pseudomonas, Rhizobium and Achromobacter, four genus for actinomyces group: Streptomyces, Kocuria, Arthrobacter and Microbacterium, two genus for fungi group: Penicillium and Fusarium. The treatment 3 have three genus for bacteria group: Chryseobacterium hispalense, Pseudomonas and Rhizobium, four genus for actinomyces group: Streptomyces, Arthrobacter, Kocuria and Rhodococcus, two genus for fungi group: Penicillium and Fusarium. Water control have six genus for bacteria group: Pseudomonas, Rhizobium, Proteus, Planococcus, Achromobacte and Stenotrophomonas. four genus for Streptomyces groups: Streptomyces, Microbacterium, Arthrobacter and Rhodococcus, six genus for fungi group: Verticillium, Acremonium, Penicillium, Cladosporium, Fusarium and Aspergillus.Among the genus obtained in this work, the Achromobacter, Proteus, Streptomyces, penicillium, Aspergillus were common in the continue using vermiculites. The Proteus vulgaris, Proteus penneri, Planococcus rifietoensis, Stenotrophomonas rhizophila, Streptomyces scabies, Streptomyces caviscabies, Streptomyces acidiscabies, Penicillium chrysogenum, Verticillium, Acremonium, Cladosporium and Aspergillus flavus were not be found in vermiculites after biocontrol.