Treating Emerald Ash Borer in Guelph & Centre Wellington

EAB Beetle and Larva

Since it was initially discovered in Canada, the Emerald Ash Borer has caused the widespread death of millions of ash trees in Southern Ontario. Unfortunately, it is has become established here in Guelph & Centre Wellington — and many of our trees are already in decline.

The township of Centre Wellington has created a management plan for municipal trees, but if you have Ash trees on your private property you will have to do something to manage the infested tree(s) yourself.

This blog will answer some common questions about Ash trees and the Emerald Ash Borer, as well as providing advice on how to manage an infested tree. Please send us an email if you have any questions!

Commonly Asked Questions

Where did the Emerald Ash Borer originate?

The Emerald Ash Borer (EAB) is a small green beetle that originated in China and was introduced to North America via wood material carried in cargo ships. It was first discovered in July 2002 in Essex County, the southwestern tip of Ontario.

Patchy-looking ash tree bark may be a sign of the emerald ash borer

Patchy-looking ash tree bark

What does the Emerald Ash Borer do?

The Emerald Ash Borer feeds on the leaves and inner bark (cambium) of ash trees. Ash become weak and brittle when infested with Emerald Ash Borer and can become a hazard very quickly. Within the next 2-4 years, we will see most untreated ash trees killed by the Emerald Ash Borer beetle.

How do I identify an ash tree in my yard?

There are a number of species of Ash (latin name – Fraxinus) in Ontario. The most common in Wellington County are: White Ash, Green (Red) Ash and Black Ash. Ash can be identified by their opposite branching, compound leaves, and distinct bark and buds.

There are many good sources online for tree identification like Ontario Trees and Shrubs or the University of Guelph Arborteum website.

Serpentine galleries left by emerald ash borer larvae in the cambium bark layer

Serpentine galleries left by larvae in the cambium

What are the signs of an Emerald Ash Borer infestation?

If you are looking for signs of the Emerald Ash Borer on your trees, then you should look for the following telltale signs:

  • A thinning, defoliated crown of the tree
  • Patchy-looking bark and vertical cracks in the bark
  • Green suckers growing from branches and main stem (epicormic growth)
  • Woodpecker damage in the bark (from the woodpeckers feeding on the larvae)
  • Bark that peels off to reveal S-shaped galleries in the inner bark layer (cambium)

Managing Ash Trees with Emerald Ash Borer

1. Assessment

Before making any decisions about management, assessing the health of your Ash tree should be the first priority. You can look for the above signs yourself, but, in most cases, the damage to the bark is only visible in the higher parts of the crown until the infestation is very severe.

We recommend that you schedule a consultation with our team of professional arborists, who can climb the tree for a more detailed assessment.

2. Treatment

Healthy trees with good structure can be injected with TreeAzin, which reduces fertility in the insect and reduces its growth rates. If regular, follow-up treatments continue to be performed, these injections can be effective for trees that are in good health. However, there is no permanent treatment option for protecting Ash trees from the Emerald Ash Borer.

The cost of treatment for homeowners with many Ash trees or very large Ash trees can be very expensive. Some municipalities in Ontario have treated certain trees to extend their lifespan and spread the high cost of removal over a number of years. This is also an option for homeowners.

Ash tree firewood is great wood to burn when "green" (freshly cut)

Ash tree firewood is great wood to burn when “green” (freshly cut)

3. Removal

Left standing, infested Ash trees can become a serious hazard. Trees infested by the Emerald Ash Borer will grow progressively weaker and may break unpredictably. Ash are also prone to root rot and tend to topple over after death. Due to this, proactive removal is recommended in untreated trees.  

All untreated ash will die and need to be removed, so we recommend that you act soon if you have Ash trees on your property. Trees that are left standing until they are completely dead may require a crane or a spider lift for safe removal, which can significantly increase the cost of removal.

4. Replanting

Ensuring the future health of our urban forest is very important. Replanting after Ash trees are removed is an integral part of Emerald Ash Borer management.

Planting in open areas, prior to Ash removal, can be very beneficial, as the new tree will already be established when the infested tree is removed. Care should be taken to plant the right tree for the right location. For more on planting, stay tuned to upcoming blog posts!

If you have an Ash tree in your yard and you are wondering what steps you should take next, give us a call at (226) 383-2286. We can come to assess the tree and help you come up with a plan.

For more information on what the town is doing to manage municipal Ash trees, check out this article in the Wellington Advertiser.