Disease Note

Meria laricis on Nursery Seedlings of Western Larch in Washington. S. J. Cooley, Forest Pest Management, Pacific Northwest Region, USDA Forest Service, Portland, OR 97208. Plant Dis. 68:826. Accepted for publication 3 April 1984. Copyright 1984 The American Phytopathological Society. DOI: 10.1094/PD-68-826b.

Severe discoloration and defoliation of 2-yr-old western larch (Larix occidentalis Nutt.) seedlings in a southwestern Washington forest nursery in 1980 were caused by Meria laricis Vuill., identified on the basis of needle symptoms, location and morphology of conidia and conidiophores on needles, and cultural characteristics. About one-third of the 140,000 larch seedlings were culled because of stunting and death caused by defoliation throughout the second growing season. M. laricis has caused less severe damage on western larch at this nursery annually since 1980. Although common in European forest nurseries and in forests throughout the northwestern United States, the fungus has not previously been reported on nursery seedlings in North America.