Identification of Rhizoctonia solani AG1-IB as a causal agent of leaf blight in Cynanchum paniculatum in China

A severe disease causing leaf blight of Cynanchum paniculatum was observed in China. From the diseased plants, 24 fungal isolates were obtained. Morphological observations and nuclear conditions of all the isolates indicated characteristics of Rhizoctonia solani. The ribosomal DNA internal transcribed spacer sequences of the isolates showed more than 99 % sequence homology with published sequences of R. solani anastomosis group 1 subgroup IB (AG1-IB). All tested isolates were pathogenic and showed significant symptoms as observed in the fields. This is the first report of leaf blight of C. paniculatum caused by R. solani AG1-IB worldwide.