Damage:
The fungi invade the plant’s roots and crown, causing the plant to clog up and fail. Infected plants are inedible.
Preventing Problems:
Rotate where you grow parsley, and consider using raised beds to enhance drainage. These fungi need very wet soil conditions to grow, so keeping parsley covered with a plastic tunnel through winter often prevents problems.
Managing Outbreaks:
Pull up affected plants and compost them. Place a pile of compost on the spots where the diseased plants grew.