Hamilton, Dundas, Ancaster, Stoney Creek, Brantford, Brant: 905‑529‑5612

Burlington, Waterdown: 905‑637‑1919


Why Are There Black Spots on My Maple Leaves?

The presence of black spots on maple leaves is often a symptom of a fungal disease known as "tar spot"

Tar spot is a common issue affecting maple trees and it is caused by fungi in the genus Rhytisma. 

Why do black spots on my maple leaves happen? 

Tar spots can occur for a handful of reasons: 

  • Environmental Conditions - Black spots on your maple leaves tend to occur in conditions of high humidity and prolonged leaf wetness. Warm, wet weather in the spring and early summer create a favorable environment for the development and spread of the fungus. 
  • Leaf Litter - The fungus can survive on fallen leaves during the winter. If infected leaves are not removed and are left on the ground, the spores can re-infect new leaves in the spring. In our Fall Tree Care Tips Guide, we strongly recommend removing leaves in the fall to prevent this spread. 

Is my maple tree at risk? 

You can breathe easy. Black spots on your maple / tar spot is mostly a cosmetic issue. Your tree is not in decline or at risk of dying

Is there a treatment for the black spots on my maple leaves? 

Yes, consider getting in touch and having a spring application of our fungicide treatment applied to your maple. 

How can I prevent black spots from occurring again? 

  • Promote Air Circulation - Regular pruning ensures proper spacing between your tree and branches, improving air circulation and reducing the humidity around the tree. This creates a less favorable condition for the fungus to develop. 
  • Fungicide Treatment - A spring fungicide application can be considered. Get in touch to schedule an on-site assessment from one of our ISA-certified arborists to see if a fungicide treatment makes sense for your tree. 

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We serve homes and businesses located in Hamilton, Stoney Creek, Ancaster, Dundas, Burlington, Waterdown, Brantford, and Brant County. Call us today for a free on-site assessment by one of our ISA-certified arborists!

Hamilton, Stoney Creek, Ancaster, Dundas: 905‑529‑5612
Burlington, Waterdown: 905‑637‑1919

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