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.