Plants may suddenly wilt, lower leaves turning yellow. Plants often topple over at the point of infection which is usually near ground level. Characteristic symptoms are a brown, soft, wet rot with an associated mass of fluffy white mould which contains large hard dark bodies, called sclerotia.
A fungus that overwinters in the soil. In spring airborne spores are released which infect susceptible plants. Sclerotia can remain viable in the soil for up to seven years.
Chemical - no control available, infested plants should be removed and burnt immediately to prevent rapid spread of the disease. Do not grow susceptible plants on that site for 4 years.