In 2025 the City of Toronto treated over 5000 City-owned ash trees in parks and along the roadways, as part of the Emerald Ash Borer program.
The Emerald Ash Borer (EAB) is an invasive beetle that attacks and kills all species of true ash trees (Fraxinus sp.). It has been in Toronto since 2007 and has killed over 800,000 ash trees across the city.
An Emerald Ash Borer Integrated Pest Management program is in effect.
Since 2011, the City of Toronto has been treating select, City-owned ash trees with TreeAzin Systemic Insecticide on a 2-year rotation to control EAB populations and protect ash trees from this insect. Starting in 2025, because of a reduction in EAB populations, TreeAzin Insecticide injections will be administered on a 3-year rotation.
Injections of TreeAzin from June 1, 2025 to August 31, 2025 targetted the larvae as they feed. TreeAzin is a growth inhibitor that blocks the molting process of EAB larvae so they can not continue to grow.
TreeAzin is injected with small canisters under the bark of trees and provides protection against EAB for up to two years.
TreeAzin is listed by the Organic Materials Review Institute (OMRI) for organic use and is allowed for use under Ontario’s cosmetic pesticide ban.
The pesticide is registered by the Pest Management Regulatory Agency (PMRA) of Health Canada for EAB control in ash trees. Any health concerns can be directed to the Pest Management Information Service on the PMRA website.
For more information please visit: Toronto.ca/EAB