High Frequency of Finding Double-stranded RNA in Naturally Occurring Isolates of Rhizoctonia solani

Forty-nine out of 50 field isolates of the basidiomycete Rhizoctonia solani were found to contain dsRNA. The presence of dsRNA appeared to have no consistent association with the degree of pathogenicity (virulence) of the isolates. These findings contradict previous reports correlating the presence of dsRNA with hypovirulence in R. solani.