What is Dutch Elm Disease?
Dutch Elm Disease (DED) is a deadly fungus disease that can infect and kill an elm tree by clogging its water conducting vessels. In Saskatchewan, the disease is spread by the native elm bark beetle. 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.
DED first appeared in Saskatchewan when one infected elm was discovered in Regina in 1981. DED has since become well established in the southeastern and northeastern areas of the province, having spread from Manitoba where it has been a problem since the 1970’s.
In Weyburn, one case of DED was confirmed in 1991. Following its removal, the City of Weyburn remained disease-free until the summer of 2001, when an infected tree was located on provincial property in the vicinity of the Souris Valley Extended Care Center. The diseased tree was immediately removed by city staff and no additional infected trees have since been found during regular surveillance of the area.
During regular surveillance in summer of 2019, samples of suspected infected trees were sent off for laboratory analysis. Unfortunately, these trees have tested positive for DED. Infected trees were found in the northwest corner of the city on Scott St. as well as on 12th St. Qualified Parks Department Staff are in the process of removing these trees to ensure the disease does not spread.
The disease has also been identified in Estevan, Carlyle, Fillmore, Yellow Grass and Trossachs areas.
There are approximately 2,200 elms growing in Weyburn’s urban forest, roughly half of which are located on City of Weyburn property. All of these trees continue to be at risk of contracting DED.
How Can I Tell if My Elm has DED?
As early as June, the leaves on a DED-infected elm will wilt, turn yellow, then curl and brown. Symptoms usually appear first in the tree’s crown and can be seen until fall colours appear. These symptoms do not guarantee the presence of DED as there are other diseases which exhibit similar symptoms. The only method to positively confirm the disease is through laboratory analysis.
If you suspect any elm of having DED, please email the Parks Department or call (306) 848-3290. We will inspect the tree and, if necessary, take samples to be analyzed in the laboratory. As the City of Weyburn considers DED prevention of utmost importance, this service is provided free of charge.
Pruning and Disposal
Keep your elms healthy by pruning dead or dying branches. Promptly dispose of any elm material at the landfill. Elm wood left laying around can harbor the native elm bark beetle. Provincial regulations prohibit the pruning of elm trees between April 1 and Aug. 31. 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.
City of Weyburn Prevention
Weyburn possesses a natural buffer zone. There are no native stands of elms lining rivers and waterways which can ease the progression of the disease. While this is an advantage, it does not mean we can be any less vigilant regarding disease prevention and control.
The City of Weyburn has a successful DED prevention and control program. Virtually all aspects are performed by fully trained and qualified Parks Department employees. The City employs a schedule where pruning occurs every fall and winter, resulting in each city-owned tree being pruned every five years. Basal spraying is also done to privately-owned elms following the receipt of written authorization from the property owner.
If you have any questions or concerns regarding Dutch Elm Disease, please do not hesitate to contact the City of Weyburn Parks Department at (306) 848-3290, or the Saskatchewan government at 1-800-567-4224.