Prevent the Spread of EAB Across Canada: How You Can Help Save Ash Trees

The Emerald Ash Borer (EAB) has affected millions of ash trees in North America. In Canada alone, EAB has spread from coast to coast, affecting ash trees in communities across Nova Scotia, New Brunswick, Québec, Ontario, Manitoba and British Columbia. 

While entomologists and urban foresters have come up with strategies to control this invasive pest, many of us may struggle with how to prevent an outbreak from spreading beyond a quarantine zone. Here are a few tips that can help mitigate the spread: 

Tip 1: Know what an ash looks like!

Many municipalities where EAB has yet to be detected are encouraging residents to speak up if they see an ash tree that looks damaged or that is dying. 

Before you can speak up, though, knowing what an ash tree looks like might help! Ash trees that are native to Canada are deciduous, and some common examples found in our cities include white ash, black ash, and green/red ash. Ash trees are medium to large trees with generally slightly furrowed bark and large compound leaves (with 5 to 9 leaflets). 

Tip 2: Know the signs and symptoms

Sadly, new infestations of EAB are difficult to detect, and usually by the time signs like physical damage and symptoms (i.e., the tree’s response to the attack) are observed, the tree can already be heavily infested. 

The common signs are: 

• S-shaped larval gallery 
• D-shaped beetle exit hole 
• Feeding notch in the leaf 
• Woodpecker activity 

And the common symptoms are: 

• Dead branches 
• Vertical bark cracks 
• Heavy seeding 
• Thinning crown 
• Premature yellowing of foliage 
• Epicormic shoots on main stem and/or major canopy branches 

Early detection is very important, so if you do notice any of these signs and symptoms, contact your municipality right away. The beetle can spread very quickly, and chemical treatments can only be used on trees that exhibit 30% or less canopy dieback.

Tip 3: Don’t move firewood

Moving firewood from a regulated area infested by Emerald Ash Borer to a non-infested area is a fineable offense. This simple act is thought to be the primary way that EAB has managed to spread so quickly throughout Canada. 

If you are not sure whether your area falls within a quarantine zone or not, we recommend erring on the side of caution – buy firewood at your destination instead and don’t move it around. 

Tip 4: Join the resistance

An easy way to prevent the spread is to stay informed on what your community is doing. 

Municipalities that have successfully protected their remaining ash trees often have a formal EAB strategy in place. Check to see if your community has one. If not, consider writing to your local council or parks department to ask for a proactive plan to monitor, treat, and replace ash trees affected by EAB. Let them know this issue matters to you and that investing in urban forestry is critical to climate resilience and healthy communities.