Monitoring

Signs and Symptoms of Emerald Ash Borer

Monitoring ash trees and reporting EAB signs to 311 will trigger the early response needed to save our urban forest.

Click HERE to upload a form to carry with you while monitoring.

General symptoms of pest activity are changes in plant growth or appearance that may indicate a problem.

The damage to ash trees occurs when larvae populations increase and feed on the inner tissues, interfering more and more with the tree’s ability to circulate life-sustaining water and nutrients. A signature of EAB are the S-shaped feeding galleries/tunnels of larvae slicing across inner tissues, severely disrupts circulation. The tree’s health declines over time with its leaves losing their rich green color and become smaller.

These signs and symptoms also mimick stress responses to growing along busy streets, in confined concrete planters near parking lots, poor soil quality, compacted soils limiting oxygen for root development, heat islands and drought.

Symptoms to look for:

  • Overall thinning of tree canopy. EAB activity mostly takes place in the higher parts of the ash tree canopy. Research supports noted changes of leaf colour from deep green to lighter, lime coloured leaves and smaller leaf size. See gradual canopy thinning images below (source: Smitley et al., 2008).

  • Chlorosis/Yellowing of leaves.

  • Branch dieback/Dead or dying branches.

  • Cracks in branches or tree trunk.

  • Epicormic shoots/new, thin twigs growing at base of tree and/or midway up tree trunk.

  • Woodpecker activity. This looks like white/blonde patches of bark that been flecked off. Only nearby woodpecker habitat supports this symptom.

Signs of pest activity and damage to plant health are a confirmation of the cause. Look for:

  • D-shaped insect exit holes in tree bark. They are roughly 1/8” in size. Note, there are other wood-boring insects that can cause exit holes in ash trees. Only the D-shape is specific to and characteristic of the Emerald Ash Borer beetle.

  • Adult insect presence on leaves or tree bark.

  • Egg masses found in the cracks and crevices of the tree bark. They are roughly 1 mm in size.

  • City staff will look for additional signs of EAB after collecting branch samples for further analysis in their labs. These include S-shaped, serpentine feeding galleries/tunnels, and larvae presence in inner bark tissues.

What to do if you find an Emerald Ash Borer beetle:

Call 311 to immediately report your finding.

Place it in a clean plastic bottle to keep it from being crushed. This makes it easier to identify. Be sure to record the exact location of the tree where it was found.

Place the container in the freezer. This will preserve the insect for closer inspection.

Do not peel or remove tree bark to look for EAB larvae or galleries. This will cause significant harm to the tree, invite infection, and ultimately result in tree death. City of Edmonton entomologists and staff have authority to perform further field investigations for confirmation of EAB on public trees.

Taking Action

Monitoring can be as simple as walking your neighbourhood, correctly identifying an ash tree, and looking for signs and symptoms of EAB on a regular basis. The best time to start is late May and continue into October.

Others may wish to map out a walking route where ash trees are in their neighbourhood.

In Edmonton, this is the LINK and a few easy steps to follow:

1. Choose ‘Genus’ from the right side dropdown menu and click on ‘Fraxinus’. Then ‘Apply’.

2. Zoom in on the map to find your neighbourhood and street area you wish to monitor.

3. Zoom in closer to find the ‘Tree ID number’. This will be helpful for the city to correctly pinpoint the tree you are reporting for further inspection.

In Calgary, this is the LINK and a few easy steps to follow:

  1. Zoom in to find your neighbourhood.

  2. Ash trees, Fraxinus species are a lime green colour.

Collecting specific information/data about a tree is an important part of monitoring. Consider carrying a small notepad, pencil, camera, binoculars, and/or cellphone.

Video: “Talking about Emerald Ash Borer”, CFIA

Report signs, symptoms and/or discovery of EAB to 311.