Disease Note

Phytophthora cryptogea and P. drechsleri Associated with Root-Rotted Douglas-Fir Seedlings in British Columbia. P. B. Hamm and E. M. Hansen, Department of Botany and Plant Pathology, Oregon State University, Corvallis 97331, and J. R. Sutherland, Canadian Forestry Service, Victoria, BC. Plant Disease 69:361, 1985. Accepted for publication 9 December 1984. Copyright 1985 The American Phytopathological Society. DOI: 10.1094/PD-69-361a.

In February 1984, 2-yr-old bare-root Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings with symptoms typical of Phytophthora root rot (stunting, chlorosis, poor rootdevelopment) were infrequently found in a coastal forest nursery in southwest British Columbia.  Phytophthora cryptogea Peth. & Laf. and P. drechsleri Tucker were isolated from diseased roots using cornmeal agar containing 20 μg/ml pimaricin.  This nursery has relatively heavy (clay) soils, characteristic of forest nurseries in Washington and Oregon with Phytophthora-root-rot problems.  This is the first report of Phytophthora root rot in a forest nursery in British Columbia and extends the northern range of this disease on Douglas fir.

References: Hansen, E. M., et al. Plant Dis. Rep. 63:307, 1979.