Disease Note.

Virus Disease of Pleurotuspulmonarius in North America. L. W. Stobbs, Agriculture Canada, Vineland Station, Box 6000, Ontario, LOR 2E0, Canada. J. G. Van Schagen, Agriculture Canada, Vineland Station, Box 6000, Ontario, LOR 2E0, and D. L. Rinker and G. Aim, Horticultural Research Institute of Ontario, Vineland Station, LOR 2E0 Canada. Plant Dis. 78:101. Accepted for publication 4 October 1993. Copyright 1994 The American Phytopathological Society. DOI: 10.1094/PD-78-0101A.

Virus-infected oyster mushrooms (Pleurotus pulmonarius (Fries) Quelet) obtained from a mushroom producer in Idaho and two mushroom producers in southern Ontario exhibited distorted sporocarps and deformed stipes (2). Production was severely reduced, particularly on second and third breaks. Coinfection of sporocarps with two spherical viruses 26 and 32 nm in diameter was detected by electron microscopy from sporocarp tissues at each location. Electrophoresis revealed six major dsRNA segments (approximately 2.15, 2.08, 1.94, 1.85, 1.72, and 1.56 kbp) and one minor segment (7.68 kbp) in all infected tissues. No dsRNA was detected in healthy sporocarps. Coelectrophoresis with dsRNA associated with cucumber mosaic and tobacco mosaic viruses established approximate M, of 2.03, 1.34, 1.27, 1.13, 1.03, 0.87, and 0.68 × 106, respectively. Four of these segments (1.34, 1.13, 1.03, and 0.87 × 106) are similar in size to those reported in virus-infected P. sapidus (Schulzer) Kalchbremer (1). The other three segments (2.03, 1.27, and 0.68 × 106) are described for the first time in virus-infected P. pulmonarius