This study was conducted to selection and investigate appropriate conditions for mass production of antagonistic microbes to control cobweb disease caused by Cladobotryum mycophilum. A grampositive bacterium was isolated from spent substrate of Agaricus bisporus and showed significant antagonistic activity against Cladobotryum mycophilum. The bacterium was identified as Bacillus altitudinis. based on the cultural, biochemical and physiological characteristics, and 16S rRNA sequence. The isolate is saprophytic, but not parasitic nor pathogenic to cultivated mushroom whereas it showed strong inhibitory effects against C. mycophilum cells in vitro. The control efficacy of B. altitudinis HC7 against cobweb disease of C. mycophilum was up to 78.2% on Agaricus bisporus. The suppressive bacterium may be useful for the development of biocontrol system. To define the appropriate conditions for the mass production of the Bacillus altitudinis HC7, we have investigated appropriate culture conditions and effects of various nutrient source on the bacterial growth. The appropriate initial pH and temperature were determined as pH 6.0 and 30oC, respectively. The appropriate concentration of medium elements for the growth of pathogen inhibitor bacterium(Bacillus altitudinis HC7) was determined as follows: 3.0% soluble startch, 10% soytone, 1.0% (NH4)2HPO4, 1.0 mmol KCl, and 0.5% L-asparagine.

Fluorescent bacteria were isolated from sporocarps that browned into various mushrooms during survey at places of the production in Korea. We examined the pathogenicity, biodiversity, and genetic characteristics of the 19 strains identified as Pseudomonas tolaasii by sequence analysis of 16S rRNA and White Line Assay. The results emphasize the importance of rpoB gene system, fatty acid profiles, specific and sensitive PCR assays, and lipopeptide detection for the identification of P. tolaasii. As a result of these various analyses, 17 strains (CHM03~CHM19) were identified as P. tolaasii. The phylogenetic analysis based on the 16S rRNA gene showed that all strains were clustered closest to P. tolaasii lineage, two strains (CHM01, CHM02) were not identified as P. tolaasii and have completely different genetic characteristics as a result of fatty acids profile, specific and sensitive PCR, lipopetide detection, rpoB sequence and REP-PCR analysis. Pathogenicity tests showed 17 strains produce severe brown discolouration symptoms to button mushrooms and watersoaking of sporophore tissue within three days after inoculation. But two strains did not produce discolouration symptoms. Therefore, these two strains will be further investigated for correct species identification by different biological and molecular characteristics.