First report of Ilyonectria robusta causing rusty root of Asian ginseng in China.
Asian ginseng (Panax ginseng) is an economically important perennial herb, mainly cultivated in Jilin Province, China. In September 2013, Asian ginseng plants in Jilin showed rusty root symptoms. Typical symptoms included rusty superficial lesions of irregular shapes and margins. Ten symptomatic roots were collected from each of five fields for investigation. To isolate the pathogen, root epidermal tissues with typical lesions were excised, surface-sterilized, and placed on potato dextrose agar amended with 50 µg/ml tetracycline. After incubation at 20±1°C in the dark for a week, 18 single-spore isolates out of 50 samples were obtained and identified as I. robusta based on morphological characteristics, DNA sequence analysis and pathogenicity test. This is thought to be the first report of I. robusta causing rusty root of P. ginseng in China.