Pictures of the Emerald Ash Borer

East Gwillimbury (EG) is working to protect our ash tree population and control invasive species like the Emerald Ash Borer (EAB).

About the EAB

The EAB is an invasive wood-boring insect to our Ash tree population. The EAB prefers all Ash tree species to complete their life cycle. The most destructive period of its life cycle is in its larval stage, between August and October.

The larvae feed on the inner bark and sapwood of the tree. This damage to the tree disrupts the movement of water and nutrients from the roots to the leaves.

The adult borer is an emerald green-winged beetle that consumes the leaves of ash trees. The adults move from tree to tree to find new host trees to complete their life cycle. Depending on the damage done, the EAB's repeated life cycles will kill the tree within a few years of the initial infestation.

EAB originates in China, Japan, Korea, and several other far eastern countries. The EAB was first discovered in Windsor, Ontario, Canada in 2002 and was first found in northern York Region in 2012.

Our strategy

We have come up with a plan to manage the effects of this infestation and are working to protect the ash tree population throughout the community. We will use the best practices of other municipalities that have been fighting emerald ash borer infestation since 2002.

We have committed to a three-phase process:

Phase one - Public awareness campaign - Ongoing

We continue to conduct public awareness on the impacts of the emerald ash borer. To learn about EAB and the EG's strategy, you can watch for notices on the Town Page or download our fact brochure for more details.

Phase two – Park and streetscape tree inventory - Completed

A tree inventory was completed in Fall 2013 by the Davey Resource Group, which has extensive municipal tree inventory experience.

The inventory focused on counting, evaluating, and mapping park and street trees.

Ash trees in open space and valley systems are being assessed on a case-by-case basis. This park and street tree inventory will assist EG with managing our urban forest to prevent similar scenarios from happening in the future.

Phase three - Management plan

Deferral treatment

Ash tree injections are being carried out to defer costs and space out removals over our five-year plan.

Removal or replacement

The most cost-effective tool for street and park trees is to remove infested trees and plant new trees of a different species in their place.

There is no efficient way to control the spread of this insect or the damages done to the trees. We expect to see a significant impact on our number of ash species in both open spaces and wood lots. We are relying on natural regeneration to replace the loss of the trees affected.

More information

For more information, you can the Town's Management Plan Report.

Regional strategy

The approach York Region is taking is a strategy involving:

  • public awareness
  • monitoring of “hot spots”
  • development and distribution of educational materials
  • removal and replacement of affected trees, and
  • limited treatment of street trees of significant value (e.g., large canopy trees, trees of cultural significance).

York Region advises that most ash trees in York Region will be dead in ten years. For more information on the Region's strategy plan, please visit York Region's emerald ash borer web page.

Helpful links


You can find answers to some of our frequently asked questions about the EAB, below. If you have more questions regarding the EAB, please contact our Parks Department.

Can I cut my ash tree down?

It is the Town's responsibility to cut it down, please do not remove the tree.

How long does it take for an ash tree to die?

Within two years of observing symptoms, most of the crown of the tree will be dead. Complete tree death typically occurs within five years but may take as few as two to three years.

Why can't my tree be treated?

Your tree may not meet the specific requirements for treatment. Trees not infested with EAB may still have other health issues. Look for extensive branch dieback, sparse foliage, conks (mushrooms) on the trunk or branches, or severe trunk injuries. These trees are not good candidates for treatment and may need to be removed for safety reasons. Treatments will cost more over time than removing and replanting with a tree that is resistant to EAB.

What does a tree infested with the emerald ash borer look like?

The tree begins to thin and die. Sprouting from the main stem of the tree may occur. Insects under the bark lead to increased woodpecker activity, which causes the tree to look like it is losing patches of bark. In severe cases, the tree's bark may split in places where the larvae are feeding beneath.

You can find evidence of the beetle. Look for small, 1/8" D-shaped exit holes, where adult beetles emerge from the trees. Exit holes may be above eye level, so it is important not to discount a symptomatic tree if no exit holes are found.

If the bark is peeled back, you can see where larvae have fed; they are usually filled with frass (sawdust and insect excrement). Larvae may also be visible underneath the bark. The cream-coloured larvae have bell-shaped segments and can be up to 1.25" in length.

What are the treatment criteria?

Ash trees that met the criteria below were candidates for treatment:

• 20 cm or greater in diameter

• Overall health and structure

• Location

• Level of EAB infestation

Will the Town be treating trees on private property?

Private property owners and residents are responsible for all costs associated with the treatment or removal of ash trees located on their property.

What kind of trees will be replanted on streets and in parks?

The Town no longer plants ash trees. We will carefully choose the type of tree to be planted based on the tree's function, the intended location and soil conditions. The tree may need to be replanted in another location in the community due to changes in underground utilities and surroundings. Residents will be informed of these relocations.

Can I choose the type of replacement tree, or what type of tree will be planted?

The replacement tree will be chosen by Parks staff from a pre-determined list according to specific site conditions.

Can I keep wood from my tree after it has been removed?

No. The wood from Ash trees must be disposed of in accordance with CFIA (Canadian Food Inspection Agency) Regulations.

What about the ash trees on private properties?

To fight the spread of the EAB, it is important for private landowners to be aware and consider the treatment and removal methods above.

Many local private nurseries and arborists can assist you in this process. LEAF is an example of an organization that assists private landowners in EAB awareness and treatment. For more information, visit their website at