Endothia canker

Endothia canker, caused by the fungus Endothia gyrosa, is a significant disease affecting the bark of broadleaf trees. As a parasitic fungus, it targets the living tissues of the stem, often resulting in sunken lesions that impair the tree's vascular system. The disease is characterized by its ability to weaken the host, making it highly susceptible to secondary invaders and eventual mortality.

The primary host for this pathogen is the Sweet Gum (Liquidambar styraciflua), though the fungus can infect various species of oaks and other hardwoods. It is especially prevalent in dense stands where humidity remains high or in areas where trees have suffered environmental stress, such as severe droughts or freeze-thaw cycles that break the physical barrier of the bark.

The most visible symptoms include depressed or distorted bark areas where the infection has set in. As the fungus develops, it produces distinct orange-to-red stromatic cushions on the bark surface, which are dense aggregates of fungal tissue containing reproductive spores. Eventually, the affected bark may slough off, exposing the dead sapwood beneath, which disrupts nutrient flow to the crown.

The development of the fungus is strictly tied to climatic factors, primarily moisture and temperature. Spore dissemination occurs via water splash, wind, or animal vectors. Because the pathogen can persist in dormant stages within the bark, it remains a threat to forest health throughout the year. Once established in a stand, it can quickly spread to adjacent trees that have any minor bark vulnerabilities.

Management and prevention focus on strictly silvicultural and sanitary practices. Removing and burning infected wood is the primary method to lower the inoculum load in an area. Maintaining tree vigor through proper irrigation and protecting stems from machinery or pest damage is essential for prevention. Furthermore, foresters should ensure that tools used for pruning are sanitized between uses to prevent the accidental transmission of spores to healthy trees.