Cause Fungal growth at the base of various conifers during the PNW rainy season has been repeatedly identified as Coniophora sp. Coniophora puteana is a known root and butt rot pathogen causing a brown rot decay of Engelmann spruce (Picea engelmannii) and other forest conifers. In the landscape, this growth has not been associated with decline, rot or structural problems of trees. It has been observed frequently on Western red cedar but also on Alaska cedar, Douglas-fir, incense cedar, Lawson cypress and Port-Orford cedar. These growths are primarily seen in northern urban areas such as the greater Seattle and Vancouver, BC areas while rarely seen in Oregon.
Symptoms Whitish to yellowish, velvety fungal growth at the base of conifers during the fall and winter. Growth occurs in the bark crevasses and can be extensive over time.
Cultural control None needed since it is not associated with damage.
References Viitanen, H. and Paajanen, L. 1988. The critical moisture and temperature conditions for the growth of some mould fungi and the brown rot fungus Coniophora puteana on wood. In 19th Annual Meeting of IRG.