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Antagonism of Scytalidium Isolates against Decay Fungi. A. E. Klingström, Assistant Professor, Department of Forest Botany and Pathology, Royal College of Forestry, S 104 05 Stockholm, Sweden, Present address: Institute of Physiological Botany, University of Uppsala, Box 540, S-751 21 Uppsala, Sweden; S. M. Johansson, Assistant Professor, Department of Forest Botany and Pathology, Royal College of Forestry, S 104 05 Stockholm, Sweden. Phytopathology 63:473-479. Accepted for publication 10 February 1972. DOI: 10.1094/Phyto-63-473.

The growth rates, celluloytic activities, production of chlamydospores, pigments, and crystals, and antagonism against four decay fungi and one blue-stain fungus of 38 European and North American isolates of three species of Scytalidium were compared. Almost all isolates degraded cellulose to some degree. Three isolates of S. aurantiacum and 10 of 28 isolates of S. album killed the four decay fungi but only weakly inhibited the blue-stain fungus. Another four isolates of S. album killed two or three of the decay fungi. In cultures of S. album, yellow pigments and crystals but not chlamydospores occurred in connection with antagonism, which was characterized by secretion of a substance that caused disintegration of the hyphae of the test fungi. Some strains of S. lignicolum killed the decay fungi without producing significant concentrations of toxic substances, indicating a different antagonistic mechanism. After incubation with S. album, wood blocks contained a toxic factor which inhibited the growth of decay fungi. The active factor was separated from the culture filtrate of one active strain of S. album. It was chromatographically purified and found to have a molecular weight of 527 by mass spectrograph analysis. The substance caused a 50% decrease in growth and respiration of Fomes annosus in artificial media at a concentration of 1 µg/ml at pH 5 but not pH 7, and stimulated the production of phenol oxidase. Pigments or crystals from cultures of active strains had no toxic effect.