Dutch elm disease is a fungal disease of elms. The fungus is spread by both a native and an introduced bark beetle whose larvae tunnel under the outer bark and create distinctive feeding 'galleries'. These adult beetles are very small (2-3 mm or 1/8 in).
The deadly fungus disease can infect and kill an elm tree by clogging its water conducting vessels. The DED fungus becomes attached to the beetles during its breeding period and is then spread as the beetle moves to healthy elms to feed and over winter. There is no cure for DED and infected trees should be removed immediately and disposed of by either burning or burial.
Signs of Dutch Elm Disease and Species most affected:
The first signs of the disease are upper branches dying and leaves turning yellow in mid-summer. Gradually, the damage spreads to the rest of the tree which eventually dies. Some trees will re-sprout from the base and the sprouts may live for a number of years.
There are three native species of elm in Canada and all have been affected to varying degrees by Dutch elm disease. The greatest impact has been on American Elm (Ulmus americana) and Rock Elm (Ulmus thomasii).Red or Slippery Elm (Ulmus rubra) is least affected by the disease
Pruning & Disposal:
Keep your elms healthy by pruning dead or dying branches. Promptly dispose of any elm material at the landfill. Elm wood left lying around can harbor the native elm bark beetle.
Provincial regulations prohibit the pruning of elm trees between April 1 and August 31st. The native elm bark beetle is most active during this period and is attracted to freshly cut elm. Provincial regulations also prohibit the storage and transportation of elm for firewood
If you have any questions or concerns regarding the Dutch Elm Disease, please do not hesitate to contact the Parks Department at 306-933-2210, or SK Environment at 1.800.SASKELM.