Dutch Elm Disease (DED) is a costly and deadly disease that affects all species of elm trees in Alberta. It is caused by a fungus that clogs the elm tree's water conducting system, causing the tree to die. The fungus is primarily spread from one elm tree to another by three species of beetles.
The beetles are attracted to weak and dying trees, which serve as breeding sites for the beetles. Once the beetles have pupated and turned into adults, they fly to healthy elms to feed, thus transporting the fungus on their bodies from one tree to the next.
Elm pruning ban is in effect from April 1 – September 30 annually.