Mammatoxin Assay for Genetic and Environmental Predisposition of Aspen to Cankering by Hypoxylon mammatum. Robert I. Bruck, Graduate Student, Department of Forest Botany and Pathology, State University of New York College of Environmental Science and Forestry, Syracuse, NY 13210. Paul D. Manion, Associate Professor, Department of Forest Botany and Pathology, State University of New York College of Environmental Science and Forestry, Syracuse, NY 13210. Plant Dis. 64:306-308. Accepted for publication 14 November 1979. Copyright 1980 American Phytopathological Society. DOI: 10.1094/PD-64-306.

Mammatoxin, a fungal toxin produced by Hypoxylon mammatum, was used to measure genetic and environmental effects on susceptibility of aspen (Populus tremuloides) to cankering. Potted aspen sprouts of four clones were preconditioned to two levels of moisture and four soil conditions. Mammatoxin lesion size from leaf bioassay was significantly affected by moisture, soils, clones, and moisture-soil-clone interactions. Lesion size was positively correlated with percentage of infection in natural stands. The leaf-toxin assay may be a fast and inexpensive method for determining genetic and site predisposition to cankering.