A total of four trees in Edmonton have tested positive for Dutch elm disease in what is the first appearance of the disease in the city.
All four have been removed and the city says it is taking “swift action” to assess all of the elm trees in the two affected neighbourhoods – Killarney and Yellowhead Corridor East – to contain the spread.
It is working with the Canadian Food Inspection Agency, Alberta’s agriculture ministry, and the Society To Prevent Dutch Elm Disease.
Symptoms of the disease were first found during a routine inspection in early August, officials say. Crews also found live banded elm bark beetles in American elm trees.
The diagnosis was confirmed by provincial lab tests on Aug. 15 and national lab tests on Aug. 27.
Two more cases were found a couple of days later.
About 22 per cent – or 90,000 – of Edmonton’s trees are elms.
In some of the city’s mature neighbourhoods, elms make up almost 100 per cent of boulevard trees.
The city expects the canvassing of Killarney and Yellowhead Corridor East for more signs of Dutch elm disease to be completed by the end of the month.
The city may also remove city-owned elm trees that have significant leaf death at the top, are small, or are located in “unsuitable growing locations,” like alleys, which will help mitigate the risk of spread, it said.
Additionally, all elms along 127 Avenue have been injected with TreeAzin Systemic Insecticide and the city has acquired the industry standard fungicide for Dutch elm disease prevention, Arbotect 20-S. Both are injected directly into trees and safe for humans and animals.
Residents are being asked to:
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not bring in firewood from another jurisdiction; -
remove bark beetle habitat by pruning and disposing of dead, dying and diseased branches October through March (pruning between April 1 and Sept. 30 is banned, as pruning can attract the beetles which spread the disease); and -
know the signs of Dutch elm disease.
