VIEW ARTICLE

Occurrence and Severity of Verticillium Disease of Mushrooms Produced on Casing (Soil) Treated with Aerated Steam. R. K. Moore, Former Graduate Assistant, presently 2nd Lieut., U.S. Army, Rocky Mt. Arsenal, Denver, Colorado 80240; P. J. Wuest, Associate Professor, Department of Plant Pathology, The Pennsylvania State University, University Park 16802. Phytopathology 63:1368-1374. Accepted for publication 17 April 1973. DOI: 10.1094/Phyto-63-1368.

Colonization of aerated, steam-treated soil by Verticillium malthousei was hindered more in soil treated at 60 and 82 C than at 98 C. Spore germination and germ tube length were reduced in soil treated at these two lower temperatures. Disease was most prevalent and yield of healthy mushrooms lowest on soil treated at 98 C and seeded 3 days before casing. Disease occurrence varied directly and yield (both weight and number of mushrooms) varied inversely with soil treatment temperatures of 60, 82, and 98 C. Similarly, disease occurrence varied directly and yield varied inversely with inoculum density.