Canker Rots
caused by P. hispidus, Poria spiculosa, Irpex mollis, and others

Many hardwood trees are susceptible, but oaks and hickories are commonly infected. Degrade and decay of hardwood lumber are the most important losses.

Identification:

Fungal fruiting bodies (conks) may be associated with the cankers and are variable. They can be toothed or pored; shelflike or flat, shortlived or persistent. Poria spiculosa produces sterile fungus material in the canker and only produces a fruiting body after tree death.

Injury:

Cankers and associated localized decay vary in size, shape, and degree of callus formation. Dead branch stubs usually are located at the centers of the cankers.

Biology and History:

Airborne spores produced by the conks land on wounded areas and initiate new infections. An internal decay column can extend rapidly, sometimes by as much as 6 to 10 inches (15 to 25 cm) annually. It normally exceeds the external canker face in length. The fungus interrupts normal decay resistance processes and eventually kills the cambium. Callus tissue may be killed when the canker expands.