This fungus primarily affects the root system and reduces plant vigor. Above ground symptoms may include stunting of terminal growth, shortening of internodes and interveinal chlorosis.
Infected roots are dark brown to black, usually starting at the root tips.
Plants with extensive root rot damage will usually decline and die during dry periods. The fungus has the ability to persist in the soil for many years, even in the absence of susceptible plants. High soil moisture and low soil temperatures favor development of black root rot. Fungicide drenches are not generally recommended for landscape use since infected plants cannot be cured. Use raised beds in landscape plantings to provide good drainage.