Your Soybean Checkoff. Rhizoctonia Seedling, Stem and Root Rot
|A typical symptom of Rhizoctonia infection is a reddish brown
lesion or canker at or near the soil line. The decay is a dry,
firm rot in contrast to the soft, watery rot caused by Pythium
or Phytophthora. Click on image to view a larger version. Photo
credit: MN Crop Diseases, Dean Malvick, University of Minnesota
Rhizoctonia root rot is caused by Rhizoctonia solani, a common
fungus present in nearly all soils. Rhizoctonia generally lives
on decaying plant residues, but can sometimes can be a
troublesome root pathogen. Infection by Rhizoctonia fungi causes
damping-off, stem rot, and root rot of soybean and other crops.
There are many strains or races of Rhizoctonia solani that
infect a wide range of vegetable and field crops. The type that
infects soybeans can also infect other legume crops, sugar
beets, some vegetable crops, and weeds. Rhizoctonia solani
survives in soil as sclerotia (resting structures) and on
decaying plant material. Sclerotia