Who and what is STOPDED?

The Society To Prevent Dutch Elm Disease (STOPDED) is a non-profit organization whose mandate is “To foster and promote the survival of the American elm (Ulmus americana) in Alberta and to protect Alberta’s landscape trees threatened by pests with emphasis on invasive alien species.”

Members include federal, provincial and municipal representatives, nurserymen, landscapers, commercial and municipal arborists, research scientists, and other interested Albertans. STOPDED members from across the province take an active role in the prevention of Dutch elm disease (DED) in Alberta and in their communities.

What is STOPDED doing in Alberta?

STOPDED is responsible for operating the Provincial DED Prevention Program. Along with all the larger cities, the society operates a full program which includes public awareness focussed on preventing the establishment of DED in Alberta. The society also monitors for the elm bark beetles that carry the disease throughout the province in many municipalities, nurseries, provincial parks and at all the Alberta/US ports of entry. Firewood is confiscated at all the ports of entry and placed in bins. STOPDED arranges to have the wood collected and dispose. STOPDED is also involved with making arrangements to have suspect DED samples taken properly and sent to the lab for diagnosis.

The society is also involved with trapping and public awareness on the Emerald ash borer. Emerald ash borer is a species of metallic wood-boring beetle native to East Asia. Ash trees are very vulnerable to this beetle, which has killed millions of trees in eastern Canada in forested and urban areas. In 2017, the borer was found in Winnipeg for the first time. It has not been found in Alberta or Saskatchewan.

Funds generated from membership dues and fund raisers are used to provide educational and promotional materials on DED prevention. STOPDED depends on public support and participation in their ongoing prevention program.

Why should we care about Elm trees?

Elm tree populations in Alberta are subject to numerous stresses. The most serious threat comes from DED, a fatal fungal disease that infects only elm trees. DED moves rapidly from infected to weakened trees on the bodies of European, banded or native elm bark beetles. The disease can kill an individual tree in as little as 3 weeks. The whole population of elms in a community can easily be destroyed within a decade.

Currently, Alberta and British Columbia are the last 2 locations in North America that are free of DED. However in 1998, one elm tree in Wainwright was confirmed to have the disease. The tree was immediately removed and burned. This tree was noticed to have typical DED symptoms by STOPDED employees while completing the provincewide elm inventory survey.

In July 2020, the City of Lethbridge had 2 elm trees that tested positive for DED at Agriculture and Forestry’s Alberta Plant Health Lab (APHL). The trees were immediately removed and city staff surveyed all elms trees for DED symptoms and elm firewood in the area where the diseased elms were found. This detection is considered an isolated case at this time, and eradication was successful.

Since 1994, the European elm bark beetle (EEBB) has been found throughout the province. In 2006, the banded elm bark beetle (BEBB) was first found in Medicine Hat. Since then, the numbers of BEBB have increased substantially throughout the city. BEBB are now found in low numbers in municipalities across the province.

Why do we need to maintain our trees?

  • Trees add beauty and give character to communities.
  • Trees reduce heating and cooling costs.
  • Trees protect us from dangerous ultraviolet radiation.
  • Trees prevent both wind and water erosion.
  • Trees convert carbon dioxide into oxygen.
  • Trees increase the value of real estate.
  • Trees reduce noise, dust and air pollution.

What can you do to help save our Elms?

  • Dutch Elm Disease prevention: What you can do
  • Take preventive measures by keeping your elm trees healthy, vigorous and properly pruned.
  • Elms should be well watered from April to mid August. To allow the trees to harden off for the winter, watering should be stopped mid August, followed by a good soaking or two before freeze-up.
  • Dead and dying elm branches and trees provide an ideal breeding site for the elm bark beetles that spread DED and must be removed. Beetles are attracted to fresh tree wounds, therefore pruning must be done between October 1 and March 31 when beetles are not active.
  • Dispose of all elm wood by burning or burying it.
  • Learn how to identify the signs of DED and beetle activity. As early as June, the leaves on a DED-infected elm will wilt, turn yellow, then curl and turn brown. This is accompanied by brown staining in the sapwood under the bark.

Become an active STOPDED member.

Do not!

  • Do not store elm firewood! It is illegal!
  • Do not transport elm firewood into or within Alberta!
  • Do not prune elms between April 1 and September 30. The beetles are active during this period; they will be attracted to the scent of fresh tree cuts, possibly infecting a healthy tree.


Dutch elm disease prevention/control measures: responsibilities and authority Under the Agricultural Pest Act

Province wide elm tree inventory update 2017


Connect with STOPDED:

Phone: 1-877-837-ELMS (3567)