Leaf spot
Round or angular brown to black spots on the leaves, often with a yellow or dark edge; the leaf yellows and drops early. Well-known examples are black spot on roses, leaf spot on celery and strawberries, and the brown blotches on horse chestnut leaves.
Various fungi and bacteria that spread by rain splash and overwinter on fallen leaves.
What can you do?
- Pick off affected leaves as soon as you see spots and put them in the green waste bin or general waste, not on your compost heap.
- In autumn, clear up fallen leaves under roses and diseased shrubs, as the disease overwinters in them.
- Water in the morning at the base of the plant and avoid wetting the leaves.
- For houseplants: give the plant more air and don’t mist the leaves.
Prevention
Choose resistant varieties, give plants space and an airy spot, and rotate vegetables every year.
When to watch out: May–September