Pocket Botanist
Check these first
- Check if the white spots rub off easily like dust.
- Ensure the plant is in a spot with good air movement.
- Look for signs of moisture trapped on the leaves.
Likely causes
Powdery Mildew
Most likelyHow to tell: You will see a white, powdery substance that looks like flour dusted over the leaves. It usually starts on older leaves and spreads to the rest of the plant.
What to do: Remove the most affected leaves immediately to stop the spread. Improve air circulation around the plant and spray the remaining leaves with a mix of one tablespoon of baking soda in a gallon of water.
Fungal Leaf Spot
PossibleHow to tell: These appear as distinct brown or black spots with yellow halos. They often develop after periods of high humidity or overhead watering.
What to do: Avoid getting water on the leaves when you irrigate the soil. Keep the plant in a spot with plenty of direct sunlight to help the foliage dry out quickly.
When to worry
It is serious if the spots cover most of the leaf surface and the leaves begin to shrivel or turn brown. Early detection is key to saving the foliage.
Stopping it coming back
Water only at the base of the plant to keep the leaves dry. Make sure your mung bean has enough space between other plants to allow for good airflow.
Not sure which one it is? Photograph your mung bean.
This page lists the usual causes. Pocket Botanist looks at your actual leaf and tells you the likely cause, how serious it is, and what to try first. Identification and a health check are free.
Questions people ask
- Is powdery mildew contagious to my other plants?
- Yes, the spores can easily travel through the air to nearby plants. It is best to isolate the affected mung bean until it is clear.
- Should I throw away the plant if it has spots?
- Not necessarily, as you can often manage it by removing infected leaves and improving conditions. Only discard it if the entire plant is overwhelmed.
More problems with Mung bean
This article was generated with AI from the plant’s care profile and is general information, not horticultural advice. Read about how we build these guides.