Dutch elm disease (DED) is caused by a fungus spread by tiny elm bark beetles that breed under the bark of dead or dying elm wood. If that wood contains the DED fungus, each new generation of beetles can infect healthy elms.
You can help prevent DED:
- Keep your own elm trees healthy;
- Don’t prune elm trees from April 1 to August 31;
- If you see signs of DED, report them to your municipal authority;
- Don’t buy, sell, store, transport or use elm firewood; it’s illegal;
- Remove and dispose of the tree promptly if DED is confirmed; and
- Support DED management in your community.
Signs of Dutch Elm Disease
Beginning in late June to mid-July, look for:
- Flagging - when the leaves of one or more branches near the top of the tree may wilt, curl, turn yellow and then brown, remaining on the tree.
- Staining - an infected twig sample will have red streaks through the sapwood (photo)
Several other diseases have similar symptoms so the only way to confirm DED is in the lab. The Ministry of Agriculture’s Crop Protection Laboratory offers free DED testing to Saskatchewan residents.
Don’t Prune Elms from April 1 to August 31
Provincial regulations prohibit pruning of elm trees from April 1 to August 31 each year. The beetles are most active then, and fresh cuts attract them, increasing the chance of infection.
If your elm needs attention during the pruning ban, because of a lighting strike or wind damage, you can remove broken branches but dispose of them right away. Contact your local municipal authority to find out about proper elm wood disposal in your area.
No Elm Firewood
It’s illegal to transport, store or buy elm firewood because firewood is one of the main ways that DED is spread in Saskatchewan. Elm bark beetles on infected firewood hitch a free ride with unsuspecting campers and homeowners, spreading the disease.
- Don’t transport firewood when camping;
- Avoid elm when cutting or buying firewood;
- Don’t store pruned elmwood to burn in a fireplace later.
Dispose of elm wood IMMEDIATELY by burning or burying; check with your local municipal authority for designated disposal sites and methods.