The Emerald Ash Borer (EAB) or Agrilus planipennis, has devastated ash trees in southwestern Ontario and parts of the United States since its discovery in Detroit, Michigan in 2002. EAB is an invasive insect pest from Asia that attacks and kills all species of ash trees. EAB is a major economic and environmental threat that has killed more than 20 million ash trees across Ontario. Let's prevent its further spread! Use our EAB and Ash Tree Identification Guide to find them and check our EAB Look-alikes first to make sure.

Also, watch the video below for a summary of the insect, the damage it causes to ash trees, and the control methods available.

Don't move firewood

The EAB can hitchhike on the firewood, hiding under the bark of logs. By not moving firewood and sourcing it near where you are going to burn it, you can avoid carrying EAB and other invasive pests, protecting trees from invasive bugs.

In Thunder Bay

We detected EAB in Thunder Bay on June of 2016. With over 25% of our City's municipal trees being ash, not including any privately owned trees, the invasion of this pest is of great concern. The city's Forestry and Horticulture section is treating eligible ash trees with the systemic biopesticide TreeAzin. This chemical is injected directly into the tree and targets EAB larvae feeding on the wood inside the trees. 

In 2021, City Council approved changed to the Emerald Ash Borer Management Strategy, namely reducing the number of trees that will be maintained with injections indefinitely and extending the plan by an additional 4 years to 2030 while staying within the original budget. This is an adaptation to the plan based on the circumstances faced by the ash in Thunder Bay.

Our Adopt a Tree Program

The Emerald Ash Borer Adopt a Tree program gives you the opportunity to sponsor the treatment of City owned ash trees. View our Emerald Ash Borer Adopt a Tree Program Poster or our Emerald Ash Borer Adopt a Tree Program Flyer to see what you need to know before submitting your request.

Program steps

  1. Contact or call City dispatch 625-2195 to inquire about sponsoring the treatment of a City owned ash tree.
  2. City Forestry staff will contact you to discuss the Adopt a Tree process and review any tree assessment or site information available for this location.
  3. If the information available rules out the potential for treatment (tree has a poor assessment rating, etc.) the process will end at this point.
  4. If the tree appears to be a candidate, we will arrange a site visit to confirm the assessment and look for any other potential site considerations that might affect approval and if pruning is required prior to injection.
  5. If approved, we will issue the approval in writing, schedule any required pruning and let you know whom to contact to schedule the injection treatment.
  6. Once the injection treatment is completed, the contractor will provide you and the City a record confirming of the work.
  7. You will be required to apply again in two years’ time to initiate the next required treatment, which will follow the same process.


Mountain ash tree

The EAB does not threaten the mountain ash, as it is not a true ash tree. It is in the genus Sorbus, while true ash trees are in the genus Fraxinus. Mountain ash have a greater number of smaller compound leaves and produce vibrant red berries in the late summer and early fall. 


Use these great resources on everything related to EAB, including particular injections and protecting ash trees:

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Tree Maintenance & Care