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Cucumber mildew
Fungal diseaseMedium impact
Powdery or downy mildew affecting cucumber foliage, weakening plants and reducing yield. Both types are common in cucumbers, particularly in late summer or in humid protected conditions.
Currently in peak season - extra vigilance worthwhile.
Key facts
- Type
- Fungal disease
- Affects
- Cucumber
- Active season
- Jul - Oct
- Peak season
- Aug - Sep
- Vulnerable stages
- Growing · Harvesting
- Spread rate
- moderate
- If confirmed
- Act soon
Signs & symptoms
- -white or grey powdery coating on leaf surfaces (powdery mildew)
- -angular yellow patches on upper leaves with grey fuzz beneath (downy mildew)
- -rapid yellowing and death of older leaves
- -reduced plant vigour and fruit production
Management
Do now
- -Remove and bin affected leaves
- -Improve ventilation and airflow around plants
- -Switch to base watering to keep foliage dry
Prevention
- -Grow in an open, well-ventilated position
- -Space plants well and train growth to improve airflow
- -Water at the base rather than over the foliage
Further reading
- -Cucumbers are prone to both powdery mildew (warm, dry spells) and downy mildew (cool, humid conditions) - they can occur at different points in the same season