What it looks like
A white powdery film on the upper leaf surface that wipes off. It spreads gradually, then the leaf yellows and drops.
Why it happened
Poor air circulation combined with high humidity and plants crowded together.
What to do
1. Cut off the worst-affected leaves and bin them — do not compost. 2. Spray with 1 part milk to 9 parts water, or a baking-soda solution (1 tsp per litre). 3. Move plants apart and improve air flow. 4. Do not water onto the leaves.
How to prevent it
Leave space between plants. Air the room occasionally. Water into the soil, not onto the leaves.
Most common on these species
- Begonia
- Polka dot begonia
- Rex begonia
- Dahlia
- Rose
- Apple tree
- African violet
- Grape ivy
- Flaming Katy
- Geranium
- Cape primrose
- Mint
- Rosemary
- Florist chrysanthemum
- Gerbera daisy
- Common sage
- Lemon balm
- Wax begonia
- French marigold
- Ivy geranium
- Pansy
- Garden chrysanthemum
- Boxwood
- Lilac
- Forsythia