Dutch Elm Disease
Saskatoon confirmed its third case of Dutch elm disease (DED) in 2021. As part of the City's DED Response Plan, the infected tree was immediately removed and disposed of at the City Landfill. Surveillance and testing of symptomatic elm trees continues throughout the city.
Saskatoon’s DED Response Plan requires:
- Immediate removal of all positive trees
- Disposal of infected trees at the City landfill
- Sampling of adjacent trees
- Surveillance and testing of private and public trees in the surrounding area with an intensive search for elm material and other sources of infection.
What is DED?
DED is a serious disease caused by a fungus that clogs the elm tree’s water and nutrient conducting system, which eventually causes the tree to die. DED was introduced in North America in the 1930s and has since wiped out millions of elms across Canada and the United States.
How is DED spread?
In Saskatchewan, the disease is spread by several species of elm bark beetles. These beetles can fly farther than two kilometres in search of elm trees. The DED fungus has tiny spores that stick to the body of the beetle. Elm bark beetles can carry these spores and infect other elm trees. The fungus can also be spread by infected pruning tools.
A tree can be infected:
- By elm bark beetles that transmit the disease
- Through root grafts between trees
- By pruning tools
American elm trees with DED may start showing symptoms as early as June. Typically, the leaves will start to wilt and turn yellow, then curl and turn brown. Residents who start to notice any of these symptoms, are encouraged to complete the online form below or call Urban Biological Services at 306-975-2890.
The most effective management strategy for DED is to not transport or store elm wood. It is imperative that elm firewood not be used at any time. It is illegal and threatens the elms that make up 25% of our urban forest.
Residents can help prevent DED by:
- Not pruning elms during the provincial pruning ban (April 1 to August 31)
- Not bringing elm wood into the city, storing elm wood for more than a day, or burning elm firewood
- Always disposing of elm wood at the City Landfill
- Sanitizing tools after working on elm trees
- Not building treehouses in elm trees, as the nail and screw holes can attract elm bark beetles
- Reporting dead or dying elm trees or branches to the City or to a professional arborist
For more information on DED:
Canadian Food Inspection Agency - Dutch Elm Disease
Saskatchewan Ministry of Environment - Dutch Elm Disease