Pocket Botanist
Check these first
- Inspect the undersides of the leaves for orange dust or tiny larvae.
- Check if the spots are blotchy and translucent or raised and powdery.
- Look for any webbing or sticky residue on the foliage.
Likely causes
Rust fungus
Most likelyHow to tell: You will see small orange or yellow pustules on the undersides of the leaves. These spots often appear during humid summer weather.
What to do: Remove and destroy any heavily infected leaves to stop the spread. Apply a copper based fungicide if the infection is widespread, following the label instructions for dosage.
Birch leaf miner
Most likelyHow to tell: These pests create brown or translucent blotches on the leaves as they feed inside the tissue. You might see small larvae if you hold a leaf up to the light.
What to do: Prune away affected leaves early in the season to reduce the population. For severe cases, use a systemic insecticide containing imidacloprid as a soil drench in early spring.
Find out what's wrong with your downy birch
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 cover more than half of the canopy or cause premature leaf drop. A few spots are normal in a wet summer.
Stopping it coming back
Keep the area around the base of the tree clear of fallen leaves to prevent fungal spores from overwintering. Ensure good airflow by spacing trees properly.
Downy birch: spots? Check yours with a photo
Every plant is a little different. Take a photo of your downy birch 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
- Will rust kill my tree?
- Usually no, it just looks unsightly. It rarely kills a mature, healthy Downy birch.
- Can I spray the leaves with water?
- Avoid overhead watering, as wet leaves encourage fungal growth. Water the soil directly at the base instead.
Guides to these causes
More problems with Downy birch
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.