Pouch Fungus
Cryptoporus volvatus (Peck) Shear

Hosts:  Ponderosa pine and other conifers

Symptoms/Signs:  C. volvatus produces small, cream-colored to tan, leathery fruiting bodies. The most distinguishing feature of C. volvatus is that it has a fungus sheath with a single hole covering the lower spore-bearing surface. This is not a heart-rot fungus, but causes a grayish white rot of the sapwood of recently killed trees.

Biology:  Insects enter, feed, and then exit fruiting bodies of the pouch fungus, carrying spores to infect recently killed or dying trees. Typically, it occurs only on dead trees and snags within 1 to 2 years after the tree’s death.

Effects:  Most commonly found on ponderosa pine in the Southwest, but can infect other conifers. This is not an aggressive pathogen, but invades a tree within the first 2 years of death. This fungus is very common in trees killed by bark beetles.

Similar Insects and Diseases:  No other conifer pouch fungus has been identified.

References:  7, 27, 29