Butternut Canker: Development on Individual Trees and Increase Within a Plantation. N. Tisserat, Former Research Associate, Department of Plant Pathology, University of Wisconsin, Madison 53706. J. E. Kuntz, Professor, Department of Plant Pathology, University of Wisconsin, Madison 53706. Plant Dis. 68:613-616. Accepted for publication 5 February 1984. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/PD-68-613.

The incidence of butternut canker, incited by Sirococcus clavigignenti-juglandacearum, increased exponentially from 5% in 1978 to 76% in 1983 within an isolated butternut (Juglans cinerea) plantation. On individual trees, cankers developed first on branches in the lower crown. Branch mortality and sporulation by the fungus followed. Trunk cankers developed 1–3 yr after initial branch mortality. Trees with tops killed by coalescing basal cankers did not resprout at the root collar. The fungus continued to colonize and sporulate on dead trees for 20 mo. Felling or treating cankered trees with a silvicide failed to prevent fungal colonization and sporulation.