Anthracnose is a common disease in southern Ontario primarily found on Maple, Oak, Ash and Sycamore. They can also be found on Redbud, Walnut, Hickory and Hornbeam. The disease is caused by a host species of the fungus Gnomonia. Usually the first infection is in the spring, when the spores can easily spread by wind and rain. Depending on the weather, Anthracnose can have multiple cycles per year if the weather remains moderately warm and wet.
Identification of anthracnose
Depending on the tree, some identification features may vary. Most common traits are leaf spots, curling of leaves and early leaf drop. The first sighting is usually the discoloured spots on the leaf surface, coloured in light to dark brown, followed by cupping and abnormal leaf growth, then leaf drop.
It is important to note that Anthracnose, Oak Wilt, Oak Leaf Blister and sometimes even Oak Gall has similar damage to the foliage of Oak trees. It is vital to properly identify what is damaging your tree in order to properly control, prevent and rejuvenate your tree effectively.
Solutions to prevent anthracnose
As a homeowner, you can easily take matters into your own hands by raking up and disposing of the infected leaves and fallen branches from the tree each year. The spores can overwinter on leaves and branches, infecting the new growth the following year. Another is providing biology and balance to the soil around your tree. This will ensure you have the beneficial fungi and bacteria that can help defend these unwanted diseases. Other integrated management treatments are available and can be provided depending on the site, time of year and the current health of the tree.