Dutch Elm Disease
American, Manchurian, and Siberian elm trees.
- The first sign is wilting leaves, a result of blocked water-carrying tubes.
- Leaves may turn yellow if trees are infected in the spring or early summer.
- Leaves may turn brown and not fall off if trees are infected later in summer.
Cause Dutch elm disease (DED) is caused by a fungus. The fungus attaches itself to various body parts of a elm bark beetle. As the beetle bores into the bark of an elm tree, the beetle introduces the fungus into the tree’s vascular system (the water-carrying tubes inside the tree). The fungus clogs these tubes and prevents the tree from transporting the necessary nutrients and water to its canopy leaves. Eventually, the tree dies because it is starved for moisture.
DED can also be spread by contaminated pruning equipment.
There is no cure for the disease; infected trees must be cut down to prevent further infection.
- Do NOT bring firewood from campsites or cabins into Regina where beetles may reside.
- Do NOT prune between April 1 and August 31 each year. Provincial legislation prohibits pruning during this period because the sap scent from a fresh cut attracts the elm bark beetle.
- Use the City's online Contact Us form or call 306-777-7000 if you suspect a private or City-owned tree in your neighbourhood has Dutch elm disease.
- When pruning is allowed, remove dead or broken branches from your private elm trees. Sterilize your pruning equipment with methanol (gasline antifreeze) between cuts. Immediately dispose of any pruned wood by taking it to the landfill. NOTE: You are not allowed to prune City-owned trees.
- Hire a licensed applicator apply a basal spray to your private elm tree in the fall. Note: You are not allowed to spray City-owned trees; the City will spray if it is required as part of their Dutch Elm Disease Control Program.