Plant Diseases

Oak Wilt

Oak Wilt
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This deadly fungal disease, which blocks a tree's water-conducting vessels, has killed millions of oaks east of the Rockies, especially in Texas and the Great Lakes states. The fungus is spread by oak bark beetles and by contact between healthy and infected roots.

Target: Oaks

Damage: Starting from the treetop down, leaves wilt turn dull, curl, dry, and drop. The tree eventually dies.

Control: Resistant varieties, controlling bark beetles. using a pruning sealer helps.

Notes: There is no cure. Remove and destroy infected trees, including stumps. Avoid pruning in spring, when bark beetles are most active. If a tree is wounded, paint over the wound immediately to deter beetles from entering. Certain fungicides can be injected into healthy trees as a preventive; consult a tree care specialist.