Dutch Elm Disease (DED) is a fungal disease caused by the pathogens Ophiostoma ulmi and Ophiostoma novo-ulmi which affect the fluid transportation system within elm trees. As the disease progresses, water and sap flow channels are clogged and leaves on individual branches turn yellow, then brown.

The disease is usually fatal to the affected tree. It is very important not to store or transport elm firewood anywhere in Canada. By law, pruning of elm trees is only permitted between October 1st and March 31st in Alberta.

DED is native to Southeast Asia but spread to Europe by way of imported products. It was first identified in Holland in 1919 and in North America by 1930. Although Alberta is DED free, the disease is prevalent in Canadian provinces to the east and American states to the south.

It spreads through root grafting of adjacent trees or may be carried by three species of beetles: the Native Elm Bark Beetle, the Smaller European Elm Bark Beetle, and the Banded Elm Bark Beetle. The beetles feed and rear young in dead and dying branches on elm trees. Upon visiting an infected elm tree, the beetles inadvertently pick up fungal spores on their body and move them to new trees.

While there are small populations of elm bark beetles established in central and southern Alberta, DED is not yet present. Most municipalities work with the Society to Prevent Dutch Elm Disease (STOPDED) to monitor local elm bark beetle populations to ensure that their elm trees stay free of the disease.

Monitoring Program

The City of Grande Prairie operates elm bark beetle traps annually to detect beetles that may be arriving in our area and provide an early warning system for DED control.

In 2017, the banded elm bark beetle was found in Grande Prairie, but Dutch elm disease is not yet present. The city has increased surveillance to track and reduce beetle populations.

City IPM crews also inspect all elm trees in Grande Prairie annually in July and August for DED symptoms such as sudden yellowing and flagging branches.


  • Provincial border crossings and weigh scales confiscate elm firewood as travellers bring it into our province.
  • Please do not transport elm firewood anywhere, or store it on your property.
  • Watch elm trees for signs of ill health, and if you are concerned about an elm tree that may have Dutch elm disease, call the Citizen Contact Centre at 780-538-0300 or email parks@cityofgp.com
  • Keep your elm tree free of deadwood by pruning during the winter months (between October 1 and March 31). Destroy all pruned wood immediately by burning or burying.
  • If you have a private elm removed, ensure the stump is ground down 10cm below the soil surface and buried with soil.

NOTE: Dutch elm disease is regulated through the Agricultural Pests Act (PDF, 458 KB) and Regulation (PDF, 399 KB). It has been identified as having the potential to be devastating to agricultural operations and natural ecosystems in Alberta, and as such, appointed inspectors may enter onto property at any time to inspect for and treat this disease. If found on your property, the disease must be controlled.

Related Links

Society to Prevent Dutch Elm Disease (STOPDED)

Dutch Elm Disease Info - Alberta Agriculture & Rural Development

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