Collybia root rot

Biotic factor that contributes to oak decline

COLLYBIA FUSIPES. Ageing toadstools of this fungus at base of Quercus coccinea (Tree No.3562). This fungus had invaded a large basal stem lesion caused in probability by Bulgaria inquinans many years previously

Extensive research in France has shown that the basidiomycete Collybia fusipes is the cause of root rot on oak (mainly pedunculate oak and red oak) and is implicated in the process of oak decline.

Infection by Collybia is often associated with a deterioration of the crown of affected trees, and this fungus is most active in dry, free-draining soils.  It is considered to be a primary pathogen and can attack the roots of vigorous trees although in the early stages disease develops slowly and only affects growth later in the infection process, sometimes after 30 years.