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Rapid Separation of Sclerotinia minor Sclerotia from Artificially and Naturally Infested Organic Soil. A. A. Abd-Elrazik, Former visiting associate professor, Department of Plant Pathology, New York State College of Agriculture and Life Sciences, Cornell University, Ithaca, 14853, Present address of senior author: Department of Plant Pathology, Assiut University, Assiut, Egypt; J. W. Lorbeer, professor, Department of Plant Pathology, New York State College of Agriculture and Life Sciences, Cornell University, Ithaca, 14853. Phytopathology 70:892 -894. Accepted for publication 4 March 1980. Copyright The American Phytopathological Society. DOI: 10.1094/Phyto-70-892.

Sclerotia of Sclerotinia minor were separated from artificially and naturally infested organic soils by a new procedure which involves wet-sieving of the soil and flotation of the sclerotia in 70% glycerol. In the procedure, soil samples are air-dried, sifted on 2-mm wire mesh, blended in tap water in a Waring Blendor, and wet-sieved through 2-mm (9-mesh) and 297-μm (48-mesh) sieves. Residue on the 2-mm sieve is discarded and the residue on the 297-μm sieve is transferred (after washing) to a centrifuge tube containing 70% glycerol. After centrifugation for 3 min at 3,000 rpm, the sclerotia in the overlying liquid are removed, counted by using a stereoscopic microscope, surface sterilized, and then plated on acidified potato dextrose agar to determine viability. The average percent recovery of sclerotia in two typical experiments by this procedure from an artificially infested organic soil was 93%. The numbers of viable sclerotia of S. minor extracted from an organic soil naturally infested with the fungus, cropped to lettuce, and sampled at the seedling stage and shortly after harvest were 10 and 30 sclerotia, respectively, per 10 g of oven dry soil.