Heterobasidion irregulare, Phellinus weirii, Onnia tomemtosa and Phaeolus schweinitzii

Root Diseases Caused By Basidiomycetes

Annosus Root Rot - Heterobasidion irregulare


Fruiting bodies of Heterobasidion irregulare. 


Asexual spores.The asexual form has been named Spiniger (old name Oedocephalum).


A cross section from the base of a red pine with Heterobasidion root rot. Tree defenses, dark red resin, can be seen at the border between infected and sound wood.

Laminated Root Rot - Phellinus weirii and Phellinus sulphurascens

Phellinus weirii

Fruiting bodies of Phellinus weirii. 


Brown setae on surface of decayed wood viewed with a hand lens.

Delamination of the decayed wood often occurs at the annual rings causing the growth rings to separate.

Phellinus weirii

The decay is a white pocket rot.


Young Douglas-fir trees with Phellinus root rot.

Stand Opening Disease of Spruce - Onnia tomentosa

Onia tomentosa

Decay in the roots at the lower trunk.

Onia tomentosa

White pocket rot caused by Onia tomentosa

Onia fruiting bodies

Fruiting bodies of Onnia tomentosa.

Brown Root and Butt Rot of Conifers - Phaeolus schweinitzii

Fruiting bodies of Phaeolus schweinitzii.


The top of the fruiting bodies have a velvety appearance.