Dutch Elm Disease Prevention

Posted On Thursday April 01, 2021

Alberta has the largest DED-free American Elm stand in the world worth two billion dollars, but we could lose it all. A new case of Dutch Elm Disease (DED) was recently confirmed in the province and has renewed calls for Albertans to follow pruning bans.

"The City of Fort Saskatchewan is home to over 3,500 elm trees and it's very important for residents to follow province-wide pruning bans (April 1 to September 30) when the beetle is most active," said Jenelle Hart, Park Services Manager, "Tree pruning is allowed from October 1 to March 31 and all branches must be burned, buried or chipped immediately."

What is Dutch Elm Disease (DED)?

DED is caused by a fungus that clogs the elm tree's water conducting system, and causes it to die. The fungus is primarily spread from one elm tree to another by three species of beetles:

 •  the smaller European,

 •  the native, and

 •  the banded elm bark beetle.

The beetles like to make their homes in weak and dying elm trees. Once they’re full grown adult beetles they leave the brood to feed on healthy elm trees– taking the deadly fungus with them! In Alberta, the Society to Prevent Dutch Elm Disease (STOPDED) monitors beetle populations throughout the year. They’ve found the beetles numbers are growing, and DED spreading faster!

How do you know if an Elm is infected?

Leaves on an infected elm will wilt, droop, curl and turn brown in mid-June to mid-July. Leaves on trees infected later in the summer will turn yellow and drop prematurely. In addition to leaf symptoms, brown stains will also appear under the tree bark.

If you think your elm tree is infected, call the STOPED hotline 1-877-837-ELMS. All DED suspect elms must be tested in a lab before more steps are taken.

What can you do the help save our precious elms?

 •  Do not prune your elms from April 1 and September 30, this is when the beetles are most active and can be attracted to the scent of fresh tree cuts. And, it’s banned in Alberta.

 •  Keep your elm trees healthy, and vigorous. Water from April to mid-August and once more before freezing temperatures arrive this allows trees to prepare for the winter.

 •  Remove dead branches and dead trees from October 1 to March 31, so the beetles don’t move in.

 •  Dispose of all elm wood immediately – burn it, bury it or chip it.

 •  Do not transport or store elm firewood at any time! You can be fined under the Alberta Agricultural Pests Act.

 •  Do not bring elm firewood across the border into Alberta! Firewood is confiscated at all the Alberta-Montana border crossings.


If you suspect an elm is infected call the STOPDED hotline at 1-877-837-ELMS.