Controlling pests is critical to preserving our urban forest.
Dutch elm disease is the invasive pest posing the biggest threat to our urban forest.
- We remove upwards of 6,000 American elms every year due to DED.
- Proactive, rapid removal of infected and dying trees is the best way to manage the disease.
Emerald ash borer is an increasing threat.
- We first detected EAB in Winnipeg in 2017. We implemented a “slow ash mortality” program to limit spread.
- We found and removed only 22 infected trees between 2017 and 2025.
- Unfortunately, we discovered a new group of EAB-infected trees in early 2026. We are now removing more infected trees and reviewing our approach to manage EAB .
We are also continually looking for damage caused by cankerworms, elm spanworm, and elm scale. We are also watching for the Asian long-horned beetle, elm zigzag sawfly, and spongy moth. These pests are damaging trees in many areas of North America, but we have not yet found established populations in Winnipeg.
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