Oak wilt was confirmed detected in Niagara Falls, Ontario, June 12, 2023 and in the Township of Springwater Ontario, June 23, 2023. This was the first confirmed detection of oak wilt in Canada. Oak wilt has not been confirmed in Toronto.
Oak wilt is a fungal disease that affects all species of oak trees. This disease will kill the tree. Oak wilt spreads by root to root contact with neighbouring oak trees, by beetles that are attracted to sap, or by moving infected firewood. Oaks in the red oak group (red, black and pin oaks) are highly susceptible, while oaks in the white oak group (white oaks, bur oaks, swamp oaks) show some degree of resistance to infection.
Symptoms
- leaves turn yellow-bronzy colour
- leaves drop early in the season (July to August)
- cracks in the bark
- white, grey or black fungus mats under the bark
- sweet fruity smell
What you can do to slow the spread
- Do not prune oak trees during the growing season (April 1 to October 31) to avoid attracting sap feeding beetles that transmit the disease. If you must prune during this time or if a branch is broken, apply wound paint to the cut area.
- Do not move firewood to prevent the spread of infected material.
- Apply good arboricultural practises to improve the general health of the trees (including watering, mulching, pruning for maintenance, and preventing injury).
- Report potential sightings of Oak wilt symptoms to the Canadian Food Inspection Agency.
What the City of Toronto is doing
- Mapping, evaluating and monitoring susceptible oak trees and oak stands.
- Implementing pruning restrictions for staff and contractors on all City-owned oak trees from April to October.
- Coordinating an oak wilt management plan along with federal and provincial agencies, and municipal forestry organizations.
