Pocket Botanist
Check these first
- Check if the leaves are wet from misting or splashing.
- Look for white dust or gray fuzzy mold.
- Ensure the plant is not in a drafty or overly humid spot.
Likely causes
Powdery Mildew
Most likelyHow to tell: A white, dusty coating appears on the surface of the leaves. It looks like someone sprinkled flour on the plant.
What to do: Increase airflow around the plant and avoid getting water on the leaves when you water. You can treat it with a fungicide or a mixture of water and a little baking soda.
Botrytis Blight
PossibleHow to tell: Gray, fuzzy mold appears on decaying leaves or stems in cool, damp conditions.
What to do: Remove all infected parts of the plant immediately. Improve ventilation and keep the foliage dry to stop the mold from spreading.
Find out what's wrong with your begonia
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
If the spots are spreading rapidly or causing the stems to rot, the plant is in danger. Small, isolated spots are easier to manage if caught early.
Stopping it coming back
Water at the base of the plant rather than overhead, and provide good air circulation.
Begonia: spots? Check yours with a photo
Every plant is a little different. Take a photo of your begonia 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.
Scan with your phone's camera to get the app
Or go to pocketbotanist.app/get on your phone
Get the app · Or check it from a photo now, free
Questions people ask
- Is the white dust harmful to me?
- It is a fungus, so it is best to wash your hands after touching it. It is not generally dangerous to humans, but it is bad for the plant.
- Should I mist my begonia?
- No, misting often leads to fungal spots. It is better to use a pebble tray if you need to increase humidity.
Guides to these causes
More problems with Begonia
- Why are my begonia's leaves turning yellow?
- What are these white bugs on my begonia?
- Why is my begonia drooping?
- Why is my begonia losing its leaves?
- How do I fix root rot in my begonia?
- Why is my begonia growing so tall and leggy?
- Why are my begonia's leaf tips turning brown?
- Why is my begonia not producing any flowers?
- Why are my begonia leaves curling?
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.