Rhizoctonia root rot of corn caused by Rhizoctonia solani AG 2-2

Abstract

A new type of lodging has been observed in some corn fields in Miyakonojo, Miyazaki, for the past 4 or 5 years. This lodging occurred when the wind was strong or relatively weak. In 1987, it was confirmed that the lodging was caused by R hizoctonia solani AG 2-2. The pathogen invaded and damaged roots. Lodging was attributed to root disease and wind velocity. In the case of lodging occur-ring when the wind was not strong, the root part of a corn plant more than 2 meter high was only a fist size. However, the corn plants was able to survive. Disease- resistance tests revealed that the 11 varieties tested were all susceptible. Furthermore, each variety of sweet corn and sorghum tested was also susceptible. The name of Rhizoctonia root rot was proposed for this new disease of corn.