what causes young bean plants to rot at the root system?
Bean Root Rots. Many fungi, including Rhizoctonia solani, Pythium species and Fusarium solani, form species phaseoli, live in the soil and will infect young seedlings or the seeds of bean plants. Seedlings fail to emerge after planting when the seeds rot in the soil or young seedlings may be stunted.
Beans may exhibit seed rot, damping-off, and root rot symptoms due to many other causes. Sclerotinia sclerotiorum which causes Sclerotinia wilt or white mold also causes a stem rot under certain conditions. The disease frequently occurs after a period of warm, humid weather.
Root rot, damping-off, and seed rots are major diseases of green beans and lima beans in some years and in some soils. These diseases are caused by a complex of soil-borne fungi; they are not seed-borne. These diseases tend to be spotty in fields, and their occurrence is unpredictable.