Green bean is the main host but lima bean, southern pea, and garden pea are also affected. It occurs mostly in hot weather in acid and poorly fertilized soils. The disease tends to be evenly distributed over a field. The disease is caused by the fungus Fusarium solani f. sp. The fungus can live in the soil several years in the absence of beans.
Infection usually occurs when the seed germinate and the fungus penetrates the hypocotyl.
A slightly reddish discoloration on the taproot occurs as early as 1 week after the plant emerges and gradually increases in intensity and extent. It may also occur in streaks that extend to the soil line. The red color may change to a dark brown and the lesions frequently crack longitudinally. The small lateral roots are usually killed, and clusters of roots may develop above the lesions and just below the soil line. Losses with this disease are usually more severe than the other root rots.