Localization of Dutch Elm Disease in 10-yr-old White Elm Clones from Resistant Parents. W. A. Sinclair, Professor, Department of Plant Pathology, Cornell University, Ithaca, NY 14853. A. O. Larsen, Experimentalist, Department of Plant Pathology, Cornell University, Ithaca, NY 14853. Plant Dis. 64:203-205. Accepted for publication 1 October 1979. Copyright 1980 American Phytopathological Society. DOI: 10.1094/PD-64-203.

The ability of ramets from some white elms (Ulmus americana and U. laevis) to resist Ceratocystis ulmi by localizing Dutch elm disease (DED) near sites of inoculation increases with age. A comparison of DED in artificially inoculated 10-yr-old ramets from localizing and normal parents showed that symptoms developed slower and were less extensive and recurrences were fewer in ramets from the localizing group. Such differences had not been demonstrable in 1- and 2-yr-old ramets of the same clones.