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Disease Note.

First Report of Meria laricis on European Larch in Wisconsin. J. Cummings Carlson, Department of Natural Resources, Madison, WI 53711. . Plant Dis. 73:81. Accepted for publication 23 November 1988. Copyright 1989 The American Phytopathological Society. DOI: 10.1094/PD-73-0081D.

Meria laricis Vuill. was indentified as the cause of needle cast of European larch (Larix decidua Mill.)seedlings at the Kayward State Nursery in Hayward, Wisconsin. Approximately 30,000 2-yr-old seedlings were infected. In early June, the tips of the needles at the base of the current year's shoots were necrotic. Infected needles shed in June and July. Defoliation was less than 25% on any one tree. Signs of the fungus, conidia and conidiophores emerging from stomata, could only be seen microscopically. M. laricis has been reported on European larch in the Canadian province of Ontatio (1) and in Europe, where severe defoliation of seedlings has occurred. This disease is also known to occur on western larch (L. occidentalis Nutt.) in the states of Washington, Idaho, and Montana and in the Canadian provinces of British Columbia and Alberta.

Reference: (1) D.T. Myren. Plant Dis. 68:732, 1984.