Hypoxylon Canker on White Oak: Stress-Induced, Often Fatal

Bark sloughing off to reveal a brownish-gray, water-repellent powder is classic hypoxylon canker. This fungus attacks stressed oaks—especially those with root damage from construction, soil compaction, or drought.

Key Facts

• Oaks are extremely sensitive to low soil oxygen; protect the entire root zone to the drip line during construction.
• No spray cures an infected tree.
• Water deeply during droughts to prolong life.
• Severely affected trees rarely recover; consult a certified arborist for a definitive assessment.

Prevention—avoiding root disturbance and maintaining tree vigor—is the only real defense.