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Home → Publications → American Chestnut Proceedings → 1978 → Interactions of Virulent and Hypovirulent Strains of Endothia parasitica on American Chestnuts in North Carolina

Interactions of Virulent and Hypovirulent Strains of Endothia parasitica on American Chestnuts in North Carolina

Rate of canker development by virulent (V) and hypovirulent (H) strains of Endothia parasitica in paired combinations on stems of American chestnut in a 0.2-hectare area were determined 12 weeks after inoculation. The analyses of variance showed highly significant treatment and replication (tree) differences in canker length, width and area, callus formation, and type of isolate recovered. In spite of large tree-to-tree variation, treatment differences within each of the three major groups, HH, HV, and VV, usually were distinct. The tree-to-tree variation is apparently due to variation in host susceptibility. Apparent conversion of virulent to hypovirulent strains occurred in34 percent of the HV treatments. Callus formation was inversely related to canker size. Sectoring in cankers by virulent isolates resulted in the appearance of diverse colony types in cultures.


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Author(s): E. George Kuhlman

Publication: American Chestnut Proceedings - 1978