After infection, round, gray to dark brown spots up to + 1 cm in size appear on the leaves. On the veins, these spots are oval and sometimes deepened. Cauliflower shows black spots.
Plants are infected through stomata. On the infected spots, spores are formed causing further spread. Warm and humid weather often lead to rapid expansion.
Where to find
- Cruciferous plants
Remove affected crops; cut away affected branches (roses).
Damaged crops from storms or hoeing, for example, are susceptible to this fungus. Keep crops literally out of the wind.