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Oak Wilt Disease
- Oak Wilt is a devastating vascular disease caused by the fungus Bretziella fagacearum. It effectively "chokes" a tree by clogging its water-conducting tissues (xylem), leading to rapid wilting and, in many cases, death.
While all oaks are susceptible, the impact varies significantly by species:
- Red Oak Group (Pointed leaf tips): Highly susceptible. Trees can die within 2 to 6 weeks of infection.
- White Oak Group (Rounded leaf tips): More resistant. They may survive for years, with only a few branches dying back at a time.
🚩 Signs of Infestation
The disease often mimics other stressors, so look for these specific red flags, usually appearing in late spring to mid-summer:
- Sudden Leaf Drop: This is the most distinctive sign. Infected trees will drop leaves while they are still partially green or bronzed.
- Browning Margins: Leaves turn a dull green or bronze, starting from the outer edges and moving inward toward the mid-rib.
- Top-Down Dieback: Wilting usually begins at the top of the canopy and progresses downward.
- Fungal Mats (Red Oaks only): In the spring following a tree's death, "pressure pads" may form under the bark, cracking it open and emitting a fruity, fermenting odor that attracts beetles.
⚠️ Note:
Note: Because Oak Wilt can look like other issues (such as Anthracnose or construction damage), it is highly recommended to have a laboratory test a sample of a wilting branch before starting expensive treatments.
There is no cure for Oak Wilt once a tree is heavily infected, so management focuses on stopping the spread.
