Stay Alert for Oak Wilt and Keep Your Trees in Check

With the warmer weather upon us, it’s important to take a closer look at our trees and keep them in tip-top shape.
In June 2023, Oak Wilt was confirmed in Niagara Falls, Ontario, as reported by the International Society of Arboriculture Ontario (ISAO). It's the first confirmed detection of Oak Wilt in Canada - and recently detected near Barrie.
A first line of defence for all your trees is to give them a yearly Deep Root Fertilization treatment. Give us a call at (905) 491-6860 or visit our website to book a summertime or fall Deep Root Fertilization treatment for your trees and shrubs.

Other ways to strengthen the health of your trees this season:

  • Pruning of oak trees should not be pruned between April and October
  • Don't move firewood (of any species)
  • Water your trees during drought, which helps keep other stresses to a minimum (e.g. spongy moth)
If you suspect your tree has Oak Wilt, contact the CFIA by completing their online submission form.

What is Oak Wilt?
Oak Wilt is caused by a fungus transmitted by bark beetles. This pest can only travel up to a few kilometers, and the fungus (of spores or root grafts) can't be transported unless physically done by humans, which is why it's extremely important to not move wood or firewood.

Signs of Oak Wilt
  • Leaves dry and drop suddenly during the summer
  • Leaves wilt or brown, first on the edges of the leaves (usually the leaves at the top of the tree are first to show signs of stress)
  • Bulges are visible under the bark where the fungus is sporulating - this leads to vertical cracks in the bark, usually seen in late fall or early spring

How to Prevent Oak Wilt From Spreading
When Oak Wilt is discovered, the infected trees should be removed and disposed of properly to prevent further spread. Burning or chipping the wood are recommended. As well, the stump must always be removed or buried. Adjacent oaks that may have been root grafted can become infected underground, yet not show signs of the fungus, may need to be removed as well. Any stored firewood logs should be de-barked or tarped.