Abstract
A description is provided for Pseudomonas tolaasii. Information is included on the disease caused by the organism, its transmission, geographical distribution, and hosts. HOSTS: Agaricus bisporus, A. bitorquis, A. arvensis, A. campestris, edible mushrooms. Also reported to cause losses on Pleurotus eryugii and P. ostreatus (65, 1655). DISEASE: Bacterial blotch of cultivated mushrooms. Spots of a pale yellow colour arise on the caps as they expand. These enlarge and become dark brown, often wet and sunken, and may coalesce. Stalks are also frequently attacked. The infection does not penetrate deeply, but renders the mushroom unsaleable. GEOGRAPHICAL DISTRIBUTION: Reported from China (62, 2744), India (57, 2373), Israel (60, 4791) Taiwan (59, 3507), Australia (NSW, Qd, Tas., Vict., 63, 3168), New Zealand (culture in PDDCC), Denmark, France (30: 554), Italy (50, 3375), Netherlands (37: 66), Rumania (42: 359), UK, USA (MD 37: 66, ME 64, 1386, MN, MO, PA 60, 2315). Probably much more widespread than these records suggest. TRANSMISSION: On one farm studied in England the primary sources of infection were the peat and limestone used in the casing process. One percent and two percent of samples respectively yielded the bacterium, which was apparently present as a normal constituent of the associated micro-flora. Water, soil spawn and spawned compost were all found to be free of infestation (Wong & Preece, 1980). Under the right conditions these low numbers are able to increase sufficiently to cause serious disease in beds. Agents of secondary spread within an infested farm are many and complex. Wong & Preece were able to isolate the pathogen from workers' hands, clothing, baskets, ladders, knives, and from cropping house floors. The organism was also trapped from the air inside and just outside infested houses, and in low numbers near the bed surfaces of apparently healthy houses. Spores discharged from diseased mushrooms seemed seldom to carry bacteria, but sciarid flies (Lycorilla sp.) and mites (Tyrophagus sp.) are able to carry infection.
Screening of homokaryotic protoclones of Agaricus bisporus (J. Lge) Imbach by colony characters and ISSR markers
