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Emerald Ash Borer

The Emerald Ash Borer (EAB) has devastated ash trees in southwestern Ontario and parts of the United States since its discovery in Detroit, Michigan in 2002. EAB is an introduced insect pest from Asia that attacks and kills all species of ash (Fraxinus) trees. Note that the mountain ash tree is not a true ash tree (Sorbus sp.) and is not threatened by this pest. EAB is a major economic and environmental threat that has killed more than 20 million ash trees in Ontario. EAB was detected in Thunder Bay on June of 2016. In Thunder Bay, with over 25% of our city's municipal trees (and an unknown number of private trees) being ash, the invasion of this pest is of great concern. Learn how to properly ID ash trees (Fraxinus) and the Emerald Ash Borer beetle and don't move firewood. Let's prevent it's further spread!

Adopt a tree program

The Adopt a Tree program provides members of the public an opportunity to sponsor the treatment of City owned ash trees that are not scheduled for treatment as part of the City’s EAB treatment program.

  • Sponsors should be aware of the following considerations prior to submitting their request:
    Sponsors must receive approval from the City Forestry and Horticulture unit prior to initiating treatment of a City ash tree. Only authorized Contractors licenced to use TreeAzin will be permitted to inject City ash trees.
  • The sponsor is responsible for all costs related to the injection treatment process for the life of the tree.
  • Estimated costs for injection range from $6 to $8 per centimeter diameter of the tree measured at breast height. E.G. injecting a 30 cm diameter tree would cost approximately $180 - $240 per treatment.
  • Injections must be completed by-annually for as long as is required (a minimum of 10 years) in order for the treatment to be affective.
  • There is no guarantee that the injection treatment will be successful in protecting the tree from the emerald ash borer infestation.
  • There is no guarantee that the City will not have to remove the sponsored tree in the future due to infestation, wind/storm damage, structural health and integrity of the tree, conflicts with utility work, etc. The City will not be held liable for any lost investment of the resident due to removals.
  • Injections must be completed during a specific period of time in the summer that lasts about five weeks starting at the end of June and ending at the beginning of August.
  • Therefore, sponsor requests should be submitted well ahead of time if possible so that pruning can be completed and the injection can be scheduled with the authorized Contractor.
  • Trees located under power lines will have to be pruned to meet clearance requirements to ensure safety during the injection process.
  • Trees that are less than 20 cm in diameter will typically not be considered for treatment as they are planned to be removed and replaced in a timely manner as part of the City’s EAB management plan, as it is more cost effective to do this.
  • Trees that are assessed as being structurally unsound will not be approved for treatment because there is a strong likelihood that they will be removed in the near future due to liability/safety risk.

Emerald Ash Borer - Adopt a Tree Program Steps

  1. Resident contacts or calls City dispatch 625-2195 to inquire about sponsoring the treatment of a City owned ash tree.
  2. City Forestry staff will contact the applicant 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 City staff will arrange a site visit to confirm the assessment and look for any other potential site considerations that might impact approval. If pruning is required prior to injection it will be identified at this time.
  5.  If approved City staff will issue the approval in writing, schedule any required pruning and instruct the sponsor to contact an authorized and licensed Contractor to schedule the injection treatment.
  6. Once the injection treatment is completed the Contractor will provide the sponsor and the City a record confirming the work has been done.
  7. The sponsor will be required to apply again in two years’ time to initiate the next required treatment, which will follow the same process noted above.

 EAB Signs

EAB and Ash Tree Identification Guide Adobe PDF, 1 page, 31 5KB

Pests that are not EAB but look similar: EAB Look-alikes

Great resource links on everything related to EAB, in particular injections/ protecting ash trees: BioForest EAB resource; Forest Invasives

If you think you have found an EAB beetle please call the CFIA at 1-866-463-6017.

    EAB Task Force

    The City of Thunder Bay, together with the Ministry of Natural Resources, Canadian Food Inspection Agency and a number of public, private and non-profit agencies have joined together as the Emerald Ash Borer Task Force Northwestern Ontario to address the threat that EAB poses to Northwestern Ontario. EAB Partners include:

    Task Force Partners

    EAB Task Force

    The EAB Task Force is currently developing strategies for EAB's arrival to the northwestern region which include:

    • What you can do - Tips for Fighting Back Against the Emerald Ash Borer


        Find out more about EAB at

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