Stem Decays and Stains
FIELD GUIDE TO INSECTS AND DISEASES OF ARIZONA AND NEW MEXICO FORESTS

Heart Rots of Oak
Inonotus dryophilus (Berk.) Murr.
Phellinus everhartii (Ell. & Gall.) A. Ames

Hosts:  Oaks

Figure 206. Inonotus dryophilus on Emory oak. Symptoms/Signs:  Oaks are host to many heartwood decay fungi. Two of the most common are I. dryophilus and P. everhartii. The former produces an annual fruiting body that degrades quickly following spore dispersal, while the latter produces a perennial fruiting body (conk) that grows a fresh sporulation layer every year.

Biology:  As with most decay fungi, branch stubs are the most common sites of infection, but entry also occurs through trunk injuries. Both fungi produce fruiting bodies on living trees.

Figure 207. Heart rot, Phellinus everhartii, on gambell oak.Effects:  Both fungi are capable of causing extensive heartwood decay.

Similar Insects and Diseases: There are many other fungi that decay the heartwood of living oak trees, but these are the most common.

References:  29, 92