Emerald Ash Borer

The Emerald Ash Borer (EAB) is a non-native invasive insect that attacks and kills most types of ash trees, including white and green ash. It originated in Asia and likely arrived in North America in the early 1990s through infested ash wood materials. It was first detected in Canada in 2002 in Windsor, Ontario. EAB has been confirmed in the City of Cornwall. 

Possible signs of EAB infestation include:

• Dead branches or discoloured foliage in late summer

• Epicormic shoots (suckers or water sprouts) on the trunk or roots when the tree is under stress

• Increased woodpecker feeding or bark damage

• Small D-shaped holes in the bark where adult beetles have emerged

• Vertical splits in the bark, often more noticeable on young trees

• S-shaped tunnels visible under the bark from larval feeding

How you can help

The most common way EAB spreads is through people moving infested materials such as firewood. To help prevent the spread, buy and burn wood locally. The City is implementing an EAB Management Strategy to reduce the aesthetic, environmental and financial impacts of the beetle. The strategy includes monitoring, treatment, ash tree removal and replacement, and public education.

What should I do if I have an ash tree on my property?

As a property owner, you are responsible for your own trees. Monitor your tree's condition and look for signs of infestation. If your ash tree appears dead or dying, contact a professional tree care company. If caught early, make sure to ask whether TreeAzin injections may help.

What should I do if I suspect EAB on my property?

Contact a professional arborist. Private property owners are responsible for trees on their property.

What will happen to a City-owned ash tree near my property?

City staff need your help to monitor City trees in your neighbourhood. If a City tree appears to be in decline, please contact us at 613-930-2787 ext. 2264. A certified arborist will assess the tree and recommend action.

City of Cornwall's approach

The City is implementing an EAB Management Strategy to reduce the aesthetic, environmental and financial impacts of the beetle. The strategy includes monitoring, treatment, ash tree removal and replacement and education.

Tree injections

Ash trees marked with a green dot at the base of the trunk are candidates for treatment with TreeAzin. This insecticide is injected into the tree to kill EAB larvae. It does not harm people, pets or wildlife and degrades naturally. 

Tree removals

Ash trees marked with an orange line on the trunk and a posted information sign will be removed. Limbs will be chipped and wood will be taken off site. The stump will be removed at a later date, and if space allows, a new tree will be planted.