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 smaller European, the native and the banded elm bark beetle.

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 leave the brood gallery and fly to healthy elms to feed, thus transporting the fungus on their bodies from one tree to the next.

Under the Alberta Agricultural Pests Act (APA) “Pest and Nuisance Control Regulation (PNCR)”, both Dutch elm disease (DED) pathogens, smaller European elm bark beetle (SEEBB) Scolytus multistriatus (Marsh), and the native elm bark beetle (NEBB) Hylurgopinus rufipes (Eichh) are named declared pests. All municipalities, counties and MDs in the province of Alberta have the responsibility and authority to prevent and control DED under the APA.

Cost of DED

In 2017 the provincial American elm inventory was updated. It demonstrated that there are at least 600,000 elms growing in Alberta municipalities, rural properties, shelterbelts and provincial parks. These elms are valued at over $2 Billion dollars. Valuations are made according to the standards developed by the Council of Tree and Landscapes (CTLA) and is used by the International Society of Arboriculture (ISA).

Removing and replacing DED infected trees pushes the costs associated with losing valuable trees even higher as it can cost over $500 dollars to remove a tree (an estimated $300 million for tree removal alone in Alberta) with the additional cost of replacing the tree.