Bacterial rot diseases of cultivted mushrooms in Japan

Research Project

Project/Area Number	60560057
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	植物保護
Research Institution	Tokyo University of Agriculture
Principal Investigator	SUYAMA Kazuo Fuculty of Agriculture, TUA. Lecturer, 農学部, 講師 (10078181)
Project Period (FY)	1985 – 1986
Project Status	Completed (Fiscal Year 1986)
Budget Amount *help	¥1,200,000 (Direct Cost: ¥1,200,000) Fiscal Year 1986: ¥400,000 (Direct Cost: ¥400,000) Fiscal Year 1985: ¥800,000 (Direct Cost: ¥800,000)
Keywords	Bacterial rot / Pseudomonas tolaasii / Identification / White line / Lentinus edodes / Pleurotus ostreatus / Flammulina uelutipes
Research Abstract	Scince 1980, bacterial rot diseases of oyster mushroom (Pleurotus ostreatus) have been found in cultivated field and markets causing severe damage in Japan. Affected mushrooms useally showed brown spot, browning and blotch symptoms resembling to brown blotch disease of Agaricus bisporus reported in Europe. Now, these diseases were commonly observed and distributed widly on cultivated oyster mushrooms or other edible mushrooms. Causal organisms were isolated from Pleurotus ostreatus, Lentinus edodes, Flammulina uelutipes and Agaricus bisporus, and were identified as Pseudomonas tolaasii according to their bacterial characteristics. Non-pathogenic fluorescent pseudomonads were isolated from diseased and healthy mushrooms together with P. tolaasii. White line was produced between P. tolaasii and non-pathogenic pseudomonads colonies when two bacteria were inoculated side to side on pseudomonas agar F. This white line was produced only between P. tolaasii and non-pathogenic pseudomonad combination, but not among the same bacterial isolates or other plant pathogenic bacteria except some isolates of P. marginalis. This reaction was specfic, and it could be used for the simple identification and detection of P. tolaasii as described by Wong and Preece (1979). By appling white line methods, P. tolaasii was detected from coated drops on cap tissue of oyster mushrooms, shelves and various materials in cultivatin room of oyster mushrooms. After hiting shelves or others, these drops turned into aerosols and were floating in the air for a long time. Aerosols containing P. tolaasii were continuously discharged under moist condition, and they are considered to be an important source of second infection for bacterial rot diseases of edible mushrooms.