Botrytis

Updated June 2026

Worst in cool, damp, still weather through autumn, winter and spring, March to October.

Botrytis, or grey mould, is a fuzzy grey fungus that rots flowers, fruit and soft growth in cool damp conditions. It strikes strawberries, tomatoes, lettuce and grapes, spreading fast through crowded plantings and on dying tissue, so airflow and hygiene keep it in check.

How to identify

• Fuzzy grey-brown mould on flowers, fruit and soft stems
• Soft brown rot on strawberries, tomatoes and grapes
• Rotting flowers and buds that fail to set fruit
• A puff of grey spores rising when an infected part is disturbed

How to prevent

• Space plants and prune for good air movement
• Water at the base in the morning and keep foliage and fruit dry
• Remove dead flowers, leaves and fruit before mould takes hold
• Avoid heavy nitrogen feeding that makes soft mould-prone growth

How to control organically

• Remove and bin all mouldy fruit, flowers and leaves promptly
• Improve airflow by thinning crowded growth and weeding
• Stop overhead watering and harvest ripe fruit quickly
• Spray an approved fungicide on valued crops in damp spells if needed
• Clear infected debris and tidy plants going into a wet season