Potato and tomato blight
Disease A rapid fungus-like disease that turns potato and tomato foliage brown and rots tubers and fruit.
What to look for
Dark brown patches on leaves, spreading fast in warm, humid weather, with white fuzz on the undersides. Fruit and tubers develop firm, brown, rotting patches.
When: July to September, in warm, wet spells.
How to prevent it
- Grow early potatoes, which are harvested before blight usually strikes.
- Choose resistant varieties of potato and tomato.
- Grow tomatoes under cover, where leaves stay dry.
- Remove any leftover potatoes (volunteers) and use certified seed.
How to deal with it
- If blight hits potatoes, cut off all the foliage and bin it, then leave the tubers for about three weeks before lifting.
- Remove infected tomato plants as soon as you see signs and bin them.
- Water at the base and keep foliage dry.
Crops it affects
If you choose to use any treatment, use only products approved for UK home gardens, follow the label and avoid spraying open flowers. See all pests and diseases.