City of Lethbridge confirms cases of Dutch Elm Disease

Samples were tested at provincial and federal labs and have since been confirmed positive for DED.

The city stated there is no evidence as to how the disease arrived in Lethbridge, but it is often introduced into a community through the transport of firewood or imported infected trees.

Healthy elm tree leaves on display (Lethbridge News Now)

“Our urban forest is an extremely important part of our community,” said Parks Manager Dave Ellis.

“To protect it, we have been monitoring tree pests and insects for many years including Elm Bark Beetles. We commonly have the Elm Beetle, like many Alberta municipalities, but none of the beetles to date, were carriers of the fungus that causes DED.”

Because of how serious the disease is, the two trees on the north side have been removed and safely disposed of. The city is now working with the provincial Ministry of Agriculture and Forestry and the Canadian Food Inspection Agency (CFIA) to develop a response plan in Lethbridge.

The good news, says Urban Forestry Technician Lindsay Bell, is that if the effected trees can be taken care of right away, Dutch Elm Disease is fairly easy to contain.

Elm trees can be injected with a fungicide in the spring to treat DED. The city says they are exploring that option. The city is also working to map the elm trees in the region and assess their condition.

Assessing the trees will help in determining how and if they can be treated.

A beetle trap (Lethbridge News Now)

Ellis touched on the seriousness of Dutch Elm Disease.

“If you look at cities in the east where they’ve had large elm populations, it has been devastating. If your street only has elms on it and they all get cut down, it’s very dramatic on your street and takes years to grow those new trees, different trees back to the same character so you can enjoy that street view like you were used to,” he said.

“It’s been devastating and hundreds and thousands of elm trees across North America have died. Most communities really don’t have much of a population.”

An Elm Bark Beetle diagnosis guide (Lethbridge News Now)

As monitoring of these trees continues, residents are asked to do the following:

Determine if they have elm trees on their property.
Watch for any signs of Dutch Elm Disease and report signs to Lethbridge 311. Signs include a sudden yellowing of leaves, eventually causing the branch to wilt and leaves to turn brown.
Refrain from pruning elm trees between April 1 and September 30.
Give the tree a good thorough watering before the fall frost to help it stay healthy through winter hibernation.
Do not keep elm wood for personal use. The city says it is illegal to do so. Stored elm wood is the ideal breeding environment for elm bark beetles.

Lethbridge is a part of the Society to Prevent Dutch Elm Disease and has been since it was first formed. The group is a non-profit whose mandate is to preserve and protect Alberta’s elm trees from DED.

Lethbridge’s urban forest features nearly 6,000 public elm trees and an estimated 5,000 private trees, making up 9.6 percent of the total urban forest.

Dutch Elm Disease does not affect other tree species. More details on DED and identifying trees can be found at the City of Lethbridge website.

Additional information on the disease from the federal government can be found here.

by Justin Goulet / David Opinko

City of Lethbridge confirms cases of Dutch Elm Disease

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