Pocket Botanist
Check these first
- Inspect the undersides of leaves for small bumps or insects.
- Check the twigs for scale insects that look like tiny bumps.
- Look for patterns in the spots to see if they are fungal.
Likely causes
Maple scale
Most likelyHow to tell: You will see small, raised bumps on the twigs or undersides of leaves that look like tiny scales. These insects suck sap and can cause yellow or brown spots to develop on the foliage.
What to do: Apply a horticultural oil spray during the dormant season to smother the overwintering insects. For active infestations, consult a professional about systemic treatments.
Fungal leaf spot
PossibleHow to tell: Small, dark, or tan spots appear on the leaves during wet, humid weather. These spots are usually cosmetic and do not threaten the life of the tree.
What to do: Rake up and dispose of all fallen leaves in the autumn to reduce fungal spores. Ensure the tree has good air circulation by thinning out crowded branches.
Find out what's wrong with your sugar maple
The list above covers the usual causes. Pocket Botanist looks at a photo of your actual plant and tells you the likely cause, how serious it is, and what to try first. Identification and a health check are free.
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When to worry
Worry if the spots cause significant leaf drop or if the tree looks weak overall. Most leaf spots are harmless and appear late in the season.
Stopping it coming back
Keep the area around the base of the tree clean of debris and ensure the tree receives plenty of sunlight.
Sugar Maple: spots? Check yours with a photo
Every plant is a little different. Take a photo of your sugar maple and Pocket Botanist tells you which cause is most likely, how serious it is, and what to try first. A few checks a day are free. Save the plant and you get care reminders timed for it.
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Questions people ask
- Are these spots contagious to other plants?
- Most fungal leaf spots are specific to maples and will not spread to your other garden plants. However, it is always good practice to clean up fallen leaves.
- Should I use a fungicide?
- Usually, no. Fungicides are rarely effective once spots appear and are not needed for the health of the tree. Focus on cultural practices like cleanup and watering.
Guides to these causes
More problems with Sugar Maple
This article was generated with AI on from the plant’s care profile and is general information, not horticultural advice. Read about how we build these guides.