City starting treatment on ash trees for emerald ash borer

Guelph, Ont., August 14, 2023 – As part of the City’s Emerald Ash Borer (EAB) plan, the City of Guelph has evaluated the condition of City-owned and shared ash trees throughout the city. Over the next few weeks, the City will be re-treating identified trees with TreeAzin®.

To be effective, TreeAzin® must be injected at least every one to two years, depending on intensity of EAB infestation. Ash trees treated in 2021 are the best candidates for retreatment in 2023.

City-owned and shared ash trees that are not being treated will be monitored and removed once they are dead, in serious decline, or are a hazard to the public. Replacement trees will be planted following stump removal, either immediately or in the next calendar year.

About TreeAzin®

TreeAzin® is a natural pest control product registered under the Pest Control Products Act that prolongs the life of trees that have EAB. The City has chosen this product for its compatibility with mammals, birds and pollinators.

About the Emerald Ash Borer Plan

The emerald ash borer (EAB) is a highly destructive, non-native, wood-boring beetle that feeds under the bark of ash trees, ultimately killing them. EAB is expected to destroy close to 100 per cent of Guelph’s untreated street, park and woodland ash trees. For more information on the City’s response to EAB, visit

For more information

Timea Filer, Urban Forestry Field Technologist
Parks Operations and Forestry, Parks
City of Guelph
519-822-1260 extension 3352
[email protected]