First Report of Rust Caused by Puccinia xanthii on Xanthium orientale subsp. italicum in China

Xanthium orientale subsp. italicum (Moretti) Greuter is an annual herbaceous plant in the Asteraceae family, native to North America. It was first found in Beijing, China, in 1991. Since then, it has spread into many provinces such as Heilongjiang, Jilin, Liaoning, Hebei, Shandong, Xinjiang, and so on. Furthermore, it has been listed as one of the dangerous quarantine weeds in China (4). This noxious invasive weed has a strong ability to acclimatize to new environments. X. orientale subsp. italicum can usually be found in alluvial flatlands, riverbanks, wastelands, roadsides, pastures, as well as farmlands. The presence of this plant decreases the native biodiversity and influences the production of agriculture and stockbreeding. In August 2013, a rust disease was first observed on X. orientale subsp. italicum in Dalian, Liaoning Province, northeast China. Various sized lesions were found on approximately one third of the leaves of each infected plant. These lesions were yellow in the early stage of infec...