VIEW ARTICLE

Variation of Hypoxylon pruinatum in Cultural Morphology and Virulence. Davinderjit K. Bagga, Former Research Assistant, Department of Plant Pathology, University of Wisconsin, Madison 53706; Eugene B. Smalley, Professor, Department of Plant Pathology, University of Wisconsin, Madison 53706. Phytopathology 64:663-667. Accepted for publication 26 November 1973. DOI: 10.1094/Phyto-64-663.

Single ascospore isolates of Hypoxylon pruinatum showed extreme variability in cultural morphology and conidial production. Only 5-6% of the isolates were conidial types. The optimum temp for growth of the fungus in culture differed among isolates and also in the same isolate on different culture media. Maximum growth usually occurred at temp from 24 to 28 C. Single ascospore isolates of the fungus showed extreme variability in their virulence to aspen, and virulence was not correlated with rates of growth in culture. Cankers developed readily on plants at temp from 12 to 32 C, although the optimum for canker development varied with the isolate.