Mushroom is cultivated as one of the major economical crops in many areas in Korea. The total production has steadily increased from approximately 186,400 M/T in 2007 to 198,563 M/T in 2009. Several bacteria are known as the causal agents of diseases of the cultivated button mushroom (Agaricus bisporus) and oyster mushroom (Pleurotus ostreatus). Pseudomonas tolaasii is the causal agent of brown blotch disease of commercial mushrooms. Colonization of mushroom caps by the bacterium results in development of brown or cream lesions on pileus and stipe. These lesions are slightly concave spots and can be round or spreading. Antagonists against P. tolaasii, HC1 were selected and their control efficacy of brown blotch disease was investigated in this study. The HC1 isolate was selected as an inhibitor of tolaasin activity by bioassay on potato and it was identified as Pseudomonas sp. by the cultural, physiological and biochemical properties and analysis of the 16S rRNA. Control efficacy of brown blotch disease by HC1 treatment was 69% on Agaricus bisporus, 68% on Flammulina velutipes and 55% on pleurotus ostreatus respectively.

The total production has steadily increased from approximately 186,400 M/T in 2007 to 198,563 M/T in 2009. Winter mushroom, Flammulina velutipes, with 61,057913 M/T in 2009, showed the highest production. Several bacteria are known as the causal agents of diseases of the cultivated button mushroom (Agaricus bisporus) and oyster mushroom (Pleurotus ostreatus). Pseudomonas tolaasii is the causal agent of brown blotch disease of commercial mushrooms. Antagonists against P. tolaasii, HC5 were selected and their control efficacy of brown blotch disease was investigated in this study. After proceeding antagonistic test, HC5 was selected as a strong antagonist against P. tolaasii and the HC5 strain was identified as P. azotoformans with the cultural, physiological and biochemical properties and analysis of the 16S rRNA. Control efficacy of brown blotch disease by HC5 treatment was 73% on Agaricus bisporus, 78% on Flammulina velutipes and 71% on pleurotus ostreatus respectively.

Cobweb disease symptoms were observed in a mushroom farm in Buye, Korea during a disease survey in 2008-2011. Five isolates of Cladobotryum sp. were obtained from the infected caps and stipes. These isolates of Cladobotryum sp. were identified as C. mycophilum based on their morphological, cultural characteristics and analysis of the ITS sequences. Early symptoms were noticed as round, fleshy, yellowish brown lesions on mushroom caps. Late symptoms progressed when the parasitic fungus formed white cobweb circular colonies on dead or damaged pinheads, spread on the surface of the casing, and covered entirely fruiting bodies. Optimal temperature and pH for mycelial growth on MEA is 23℃ and 6.0. Microscopically the spores of the fungus are large and most 2~3 celled produced on vertically branched conidiophores. Mushroom caps turned dark brown and shrunk due to soft rot. Testing of sensitivity to selected fungicides showed that isolate was highly resistance to Mancozeb and Thiophanate-methyl, moderately sensitivity to Iprodione, and highly sensitivity to Benomyl, Prochloraz-Mn and Carbendazim.

The winter mushroom, Flammulina velutipes, is one of the major economical crops cultivated in Korea. The total production have steadily increased approximately 40,161 M/T in 2005 to 61,057 M/T in 2009. Several bacteria have been known as the causal agents of certain diseases of cultivated button mushroom(Agaricus bisporus) oyster mushroom(Pleurotus ostreatus) and winter mushroom(Flammulina velutipes). It is well known as bacterial diseases of the cultivated mushroom such as brown blotch, mummy disease, bacterial pit, bacterial rot, weeping disease, ginger blotch, and drippy gill. Black rot has been recognized as a major problem within the mushroom industry. Pseudomonas tolaasii has been shown to be associated with a black disorder of the caps and stipe of the mushroom. Recently, P. tolaasii was isolated from disease cultivated winter mushrooms grown in Korea. Its symptom appeared as dark brown and sunken lesions on the caps and stipes of affected mushrooms. Inoculation of bacterial isolates into mushroom caps and stipes showed characteristic black rot symptoms and sunken lesions. Results of Gram stain, staining of flagella and biochemical tests identified these isolates as P. tolaasii. This was confirmed by pathogenicity, physiological and biochemical characteristics, and results of an analysis of the 16S rRNA gene sequences.

This study was carried out investigate to availability of commercial microbial pesticide and antibacterial activity of isolates isolated from different mushroom media. Ten commercial microbial pesticide and EM liquid were collected from different company. EM of these one has been used for control of mushroom disease and growth promotion at the mushroom farms. The density of bacteria and yeast in EM cultural liquid was higher than those of the crude liquid. The pH values of EM showed the low acid levels(pH 3.5~3.9) by organic acid secreted from microorganism. The kinds of organic acid was acetic acid, lactic acid and succinic acid. The dominant bacteria isolated from EM liquid was Lactobactillus sp.(21 strains), Acetobacter sp.(9 strains), PaeniBacillus sp.(9 strains) and others(12 strains). The organic acid bacteria isolated from fermentation foods( was 92 strains and the dominant genus was Weissella sp.(41 strains), Leuconostoc sp.(21 strains), Enterococcus sp.(9 strains), Lactococcus sp.(9 strains) and others(12 strains). And we isolated 2,500 bacteria from oyster mushroom and button mushroom cultural media for selection of antagonistic bacteria. Thirty five strains of these isolates showed very strong antagonistic activity. These strains were identified Bacillus amyloliquefaciens, Bacillus subtilis, Brevibacterium halotolerans, Pseudomonas libanensis, Stenotrophomonas maltophilia and Alcaligenes faecalis by 16S rDNA analysis.

Mushroom is cultivated as one of the major economical crops in many areas of the Korea. The total production have steadily increased approximately 151,913 M/T in 2000 to 186,400 M/T in 2007. This study was carried out to investigate applicability of mushroom production using various organic media resources within the country. Eight organic resources were collected from various areas. Pleurotus ostreatus and Fulammulina velutipes showed the highest growth at the media of 10% red ginseng marc, 20% lacquer tree, 20% Juglans mandshurica, 10% Cudrania tricuspidata, 10~20% Acer pensylvanicum, 10% Lindera glauca. Mushroom mycelial growth at red ginseng marc media was slower than that of the control. But the sponin of the red ginseng was not detected at the fruiting body grown from red ginseng marc media, And three organic resources(barly powder, sweet potato powder, potato powder) was used to substitute rice bran used in mushroom cultivation. Pleurotus ostreatus and Fulammulina velutipes showed the highest growth at 10~30% sweet potato powder, 20% barly powder and 10% potato powder.

Agaricus bisporus grows on a substrate known as compost, which is a product of aerobic fermentation by various microorganisms. These organisms convert and degrade the straw and form lignin humus complex which is utilized later on by the population of organisms. Theses microflora play a key role in the process of composting and can be regarded as the active agents in the preparation of nutrient medium as many of them may ultimately contribute themselves to the nutrition of A. bisporus. The diversity of microflora according to growing farmhouse and fruiting body of Agaricus bisporus were investigated. The aerobic bacteria and Bacillus as longer of turning stage of compost pile were increased. And, thermophilic actinomycetes and fluorescent Pseudomonas sp. showed high density after the pasteurization stage. But Tricoderma sp. was decreased toward the end of turning stage of compost pile. Ten mushroom farms was selected to research of microflora of fruiting body of button mushroom. The microflora showed significant difference according to mushroom farms. The bacteria density was 0.4~41.6×105 cfu/ml and the fungus was 1.3~3.9×103 cfu/ml. But The microorganism density was not significant change for the storage periods. These isolates were classified into Chryseobacterium indologenes(6 strains), Pseudomonas agarici(5 strains), Sphingobacterium multivorum(2 strains), Flavobacterium anhuiense(2 strains), Microbacterium sp.(10 strains), Pseudomonas sp.(13 strains) on the basis of 16 rDNA analysis. The most dominants of these species were Chryseobacterium indologenes and Pseudomonas agarici.

Several bacteria have been known as the causal agents of certain diseases of the cultivated button mushroom (Agaricus bisporus) and oyster mushroom (Pleurotus ostreatus). It is well known as bacterial diseases of the cultivated mushroom such as brown blotch, mummy disease, bacterial pit, bacterial rot and weeping disease, ginger blotch, and drippy gill. Brown blotch is the most critical cause of crop loss in the commercial mushroom industry. The classical bacterial blotch disease of mushrooms is caused by a fluorescent pseudomonad, Pseudomonas tolaasii. Affected mushrooms show lesions which become dark chocolate-brown, are wet, and deeply pit the caps and stalks. Although Pseudomonas tolaasii has been known as the casual agent of bacterial blotch, much controversy exists regarding the identification of this bacterium and whether blotch may be caused by more than one organism. This study was carried out to investigate characterization and biological control of Pseudomonas tolaasi and other possible browning pathogens isolated from cultivated mushrooms. One hundred seventy four bacteria were isolated from the cultivated mushroom and collected from main producing districts throughout the country. The isolates were classified into Pseudomonas tolaasii(20 strains), Pseudomonas gingeri(1 strains), Pseudomonas agarici(4 strains), Pseudomonas putida(11 strains), Pseudomonas sp.(46 strains), Ewingella americana(14 strains), Stenotrophomonas sp.(4 strains), and others(74 strains) on the basis of 16 rDNA analysis. The most dominants of these species were Pseudomonas tolaasii and Ewingella americana. Pseudomonad isolates were mainly divided into two groups in white line test and a sharply defined white line of precipitate forms in Pseudomonas agar F(Difco) between the opaque white colonies of P. tolaasii and translucent colonies of certain unidentified pseudomonads. The white line test was positive when 20 isolates of P. tolaasi from different countries were examined, whereas 62 isolates of pseudomonads did not give the white line reaction with a reacting translucent colony Pseudomonas. All the isolates tested for white line forming bacteria including P. tolaasi were highly pathogenic to mushroom tissue. Although browning of mushrooms in host tests does not perfectly help in the identification of P. tolaasi, a conspicuous pitting produced at the cut surface of mushroom tissue is as specific as the white line test in detecting P. tolaasii in suspension in distilled water. URP2F primers of 20-mer were used to assess the genetic diversity of white line forming bacteria. The phylogenetic tree was constructed by using the neighbor-joining method. In the analysis of RAPD pattern, all isolates of white line precipitate have some of the different genetic traits as collected districts. Phylogenetic analysis of 16S rDNA revealed that twenty isolates including white line forming bacteria were closely related to P. tolaasii and showed high similarity. To biological control on bacterial browning disease of cultivated mushrooms, six hundreds plant extracts (332 EtOH extracts, 268 water extracts) was used for control of mushroom disease. Thirty plant extracts in bacterial disease(Pseudomonas tolaasii, P. agarici, B. gladioli, E. americana) and thirty three in fungus disease(T. harzianum, C. mycophilum, V. fungicola) showed strong anti-microbes activity. They showed stronger anti-microbes activity at ethanol extracts than water extracts. MIC of extract BCW128 on Pseudomonas tolaasii was 700ppm and HDE17 was 330ppm. MIC of extract YCE107 on P. agarici was 330ppm, JGE96 was 330ppm and BCW128 was 700ppm. The bacteria inhibit tolaasin secreted by Pseudomonas tolaasii was selected three genus(Bacillus sp. etc). Now we are carrying out more research on these bacteria.