Within the City of Toronto it is estimated there are about 860,000 trees that would be vulnerable to an Emerald Ash Borer infestation. The city has worked hard to make sure the trees in public parks and on streets are well cared for to keep the city beautiful and green, so it only makes sense that all precautions must be taken to protect ash trees from this pest. Here’s what you need to know about the Emerald Ash Borer invading Toronto.


Preventative Measures

There are pesticides proven to keep the beetle from infesting trees, but the trees must be treated with this solution repeatedly sometimes multiple times a season. The city is will spray trees in public parks and on streets with this pesticide, but you may also want to do some preventative measures of your own if you have trees on your private property.


If you have healthy ash trees on your property, the city would encourage you to take all preventative measures to keep the trees healthy.


Widespread Infestation

Some preliminary surveys have shown that the Emerald Ash Borer is actually widespread across Toronto, but since signs of infestation doesn’t show until it’s almost too late it may not be know just how many trees have active infestations.


Tree Removal

If the infestation has gone untreated for too long then sometimes there is nothing that can be done to save the tree. The tree, if infested, will be almost hollow on the inside so it can easily fall over or crash at any time. The city will arrange for trees on public property to be properly removed, if needed, so that they don’t cause further damage to people or property.


If you have a tree on your property that you believe needs to be removed, you can call 311 to request an exemption from the Private Tree Bylaw provisions. There will be a series of questions you’ll need to answer. If the city determines your situation meets the requirements for removal than the city will arrange for removal. This exemption only applies to ash trees that are vulnerable to the Emerald Ash Borer.


Infestation Signs to Look For

If you aren’t sure what you should be looking for, there are a number of signs you can check for to see if there’s a chance the trees on your property are infected. Signs of an infestation may include


  • Vertical cracks in the trunk
  • Tunneling under the bark (in a zigzag pattern)
  • D-shaped holes (indicating mature bug exit from the tree)
  • Long shoots growing form the trunk with larger than normal leaves
  • Thinning or yellowing of the leaves (especially prematurely)
  • Dying branches


Saving Healthy Ash Trees

Currently, there is a naturally occurring compound known as TreeAzin. It does have pesticide properties, and it is currently the only approved product in Canada to effectively control the Emerald Ash Borer and keep ash trees alive. It is recommended that treatment start as early as June and continue into August each year to ensure maximum effectiveness against the beetle.