Rhizoctonia is one of the pathogens contributing to the root rot complex. However, it is considered less problematic than Aphanomyces and Fusarium. Rhizoctonia solani causes seed decay, damping off, and seedling blight and is commonly known as wirestem due to severe stem pinching resembling wire or thread. Later-season infections are difficult to distinguish from Fusarium. It is characterized by reddish-brown lesions on the stem and below the soil surface coupled with stem girdling, leaf yellowing, and wilting of the entire plant.
Causes
Rhizoctonia is a root rot disease caused by a soil fungus called Rhizoctonia solani. It can survive in soil or crop debris and persist for several years. Host crops include cereals, canola, alfalfa, dry beans, and, of course, peas and lentils.
Rhizoctonia solani is a soil-borne fungus that usually overwinters on previous crop residue, such as sclerotia. Environmental conditions such as cool, wet springs followed by hot, dry conditions are conducive to disease development. The most aggressive infections occur between 24–30°C. Rhizoctonia infections can be severe in light and sandy soils and are commonly found on hillsides.
