Brown felt blight
Leaf, Scale, Twig, Branch
Damage, symptoms and biology
Branch dieback or death occurs on seedlings and the lower branches of larger trees. Although rarely a problem in natural forests, this disease can cause significant loss in bare root nurseries and young plantations where sufficient snow is present.
The fungus is spread by ascospores that fall with the twigs and dead needles of infected trees. The litter, infected by the mycelium and ascospores that have fallen on the snow, is deposited on live branches under the melting snow, causing a new infection.
A brown felt forms at temperatures of just over 0oC early in the spring.
Another "snow mould" that occurs on true firs and Douglas-fir is Phacidium abietis (Dearn.) Reid & Cain, but it does not invade branches or cause dieback.
Canadian Forest Service Publications
Information on host(s)
Amabilis fir, black spruce, common juniper, Engelmann spruce, grand fir, juniper, mountain hemlock, mugho pine, Nootka false cypress, Rocky Mountain Douglas-fir, Rocky Mountain juniper, shore pine, Sitka spruce, subalpine fir, western hemlock, western redcedar, western white pine, white spruce, yew