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Dutch Elm Disease (DED)
Dutch Elm Disease (DED) is a lethal, fast-acting fungal disease that clogs the vascular system of American elm trees. Symptoms include "flagging" (yellowing/wilting leaves on upper branches), brown streaking under the bark, and rapid tree death. Spread primarily by elm bark beetles and root grafting, it is managed through fungicides, pruning, and removing infected trees.
🚩 Signs of Infestation
The disease is most visible from late spring to mid-summer. Look for these specific signs:
- Flagging: A single branch or cluster of leaves suddenly turns yellow, wilts, and then browns. This "flag" stands out against the rest of the green canopy.
- Shepherd’s Crook: The tips of young, infected shoots may curl over into a hook shape.
- Vascular Streaking: If you peel back the bark on a wilting twig, you’ll see dark brown or reddish-purple streaks in the wood. In a cross-section, this looks like a dark ring.
- Leaf Retention: Unlike natural autumn drop, DED-infected leaves often shrivel and stay attached to the branch for a long time.
Pro Tip 💡
If you see flagging, don't wait for autumn. If it’s mid-summer and one branch looks like it’s in a different season, the clock is ticking!
There is no "cure" for a tree that is heavily infected, but the spread can be managed.
