In general there are 3 types of cankers: annual, perennial and diffuse, in order of their dominance over the host. Cankers are diseases of the bark; the fungus attacks the living bark and cambium and causes sunken areas on the stem, bole deformation, stain and resin-soaking, branch flagging, top kill, decay infection sites and sometimes tree death.


Cryphonectria parasitica Chestnut blight

Host: American Chestnut
Damage: was introduced from Asia, eliminated Chestnut as a forest tree in North America.

Cryptosphaeria populina

Host: Poplar species
Damage: can quickly kill small trees, bark becomes black, stringy, sooty.

Encoelia pruinosa Sooty bark canker

Host: Poplar species

Hypoxylon mammatum Hypoxylon canker

Host: Poplar species
Damage: east of the Rockies this fungus causes significant levels of mortality of aspen, west of the Rockies it is relatively infrequent. It is a perennial canker, and produces a toxin that kills the bark. Causes a cracked, checkerboard appearance of the bark.


Atropellis piniphila Atropellis canker

Host: lodgepole pine
Damage: causes long, narrow, sunken lesions with lots of resinosus. Also stains the wood beneath the canker a dark black. Reduces lumber recovery, causes mortality. Is more frequent in high density stands.
- suspect invades at bark whorls, can invade and grow quickly in sapwood

Douglas-fir Exploding Canker

Host: Douglas-fir, spruce (could be different causal agents)
Damage: causes a target, perennial canker on both hosts, causal agent is unknown. Can eventually cause mortality, major damage from bole deformation, and decay fungi.