Hypoxylon Canker/Biscogniauxia (Hypoxylon) Canker

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Hypoxylon Canker is a fungal disease that commonly affects stressed, weakened, or declining hardwood trees, particularly oak trees. The fungus is often present in the environment and typically attacks trees that are already under stress from drought, soil compaction, root damage, construction activities, insect infestations, or other environmental factors.

• Live Oak
• Red Oak
• Post Oak
• Water Oak
• Elm
• Pecan
• Other hardwood species

Early symptoms can be difficult to detect, but common signs include:

• Thinning canopy or sparse foliage
• Premature leaf drop
• Dead branches in the upper canopy
• Declining tree health
• Sections of bark peeling or falling off
• Gray, silver, tan, or black fungal growth beneath the bark
• Large dead areas on the trunk or major limbs

As the disease progresses, bark may slough off, exposing powdery fungal spores that range from light gray to dark brown or black.

Hypoxylon Canker is usually a secondary disease, meaning it attacks trees that are already stressed. Common contributing factors include:

• Prolonged drought
• Root damage
• Soil compaction
• Construction near root zones
• Poor soil conditions
• Insect infestations
• Storm damage
• Other diseases

Unfortunately, there is no effective fungicide treatment once Hypoxylon Canker becomes established within the tree. Management focuses on improving tree health before infection occurs.

For trees showing early signs of stress, recommendations may include:

• Proper watering during drought conditions
• Mulching around the root zone
• Reducing soil compaction
• Professional pruning of dead branches
• Tree health assessments
• Fertilization or nutrient management when appropriate

If a tree has extensive canopy dieback, major trunk infection, or significant structural decline, removal may be the safest option. Trees affected by Hypoxylon Canker can become brittle and prone to branch failure, creating hazards for homes, vehicles, and people.

• Water trees during extended dry periods
• Avoid damaging roots during construction
• Maintain proper mulch rings
• Schedule regular tree inspections
• Address insect and disease issues early
• Prune trees properly using ANSI-informed practices

At CBM Tree Service, tree health assessments can help identify stress factors and early signs of decline before conditions such as Hypoxylon Canker lead to hazardous tree failures. Early detection is often the best defense against this disease.