New Host Record of Myrothecium roridum Causing Leaf Spot onAbutilon megapotamicum from China

During September 2010, Abutilon megapotamicum plants with dark-brown concentric spots on leaves were observed in a commercial glasshouse located in Beijing, China. This study was carried out to identify the causal agent of this disease based on Koch's postulates and morphological characteristics. Pathogenicity tests in the glasshouse showed that Myrothecium roridum Tode ex Fr. caused the leaf spot on A.megapotamicum plants, which were the same as those observed in naturally infected plants in the field. Moreover, to confirm the pathogen to species, the rDNA internal transcribed spacer (ITS) of isolate was PCR-amplified using ITS1 and ITS4 primer pairs and sequenced. DNA analysis revealed a 100% species identity index for M.roridum. To the best of our knowledge, this is the first report of M.roridum on A.megapotamicum in China.