Powdery mildew
DISEASE
When it's active · UK
JFMAMJJASOND
When it's active · Northern Italy
JFMAMJJASOND
When it's active · Central Italy
JFMAMJJASOND
When it's active · Southern Italy and islands
JFMAMJJASOND
How to recognise it
White-grey, dusty or powdery coating on leaves, stems and sometimes buds.
Life cycle and conditions
Favoured by dry soil at the roots combined with humid air around the leaves; spreads fastest in warm, still conditions with fluctuating humidity.
Prevention
Keep soil consistently moist, especially in dry spells; improve airflow by not overcrowding plants; choose resistant varieties where available.
How to treat it
🌿 ORGANIC · RECOMMENDED
Remove and dispose of badly affected leaves and improve airflow; a traditional sulphur-based spray, long used in organic growing, is a low-impact option at the first signs where still approved for amateur use.
🧪 CHEMICAL · IF YOU CHOOSE
Few synthetic fungicides remain approved for amateur UK use; the sulphur-based option above usually covers most needs without reaching for a stronger product.