What is causing our maple trees to have black spots on the leaves?
Our maple trees have big black spots on the leaves. My guess is it’s a fungus; is that likely? For now, assuming it’s a fungus, what’s the best product to treat it with? The maples are fairly new and small, so spraying would be possible.
From what I can see, it appears to be a type of white oak tree with anthracnose. This has been a “good” year for anthracnose, which thrives in cool, wet spring weather. Here’s a helpful fact sheet that outlines the disease and management strategies: https://extension.umn.edu/plant-diseases/anthracnose-trees-and-shrubs
A few quick facts to note from the linked resource:
- Anthracnose is a common fungal disease of shade trees that results in leaf spots, cupping or curling of leaves and early leaf drop.
- . . . is most common in cool, wet spring weather.
- Anthracnose is not a significant threat to the health of the tree and doesn’t require treatment in most cases.