First record of Melampsora medusae in China
Surveys on rusts of poplars were conducted in China in 2015-2018 in the provinces of Beijing, Gansu, Henan, Inner Mongolia, Qinghai, Shaanxi, Shanxi, and Sichuan. They were triggered by the fact that severe rust symptoms were developing on Populus deltoides which were known to be resistant to the native rust M. larici-populina. Melampsora medusae (EPPO A2 List) was identified (morphologically and by sequencing) in 4 locations in Sichuan (on P. deltoides, P. simonii, P. szechuanica and P. yunnanensis) and in 1 location in Shaanxi (on P. deltoides). Further surveys also identified M. medusae in Henan and in additional locations in Sichuan and Shaanxi. The aecial host of M. medusae in China is not yet known. The authors noted that M. medusae was often found in proximity to M. larici-populina, and that both fungal species could hybridize.
The situation of Melampsora medusae in China can be described as follows: Present, restricted distribution (Henan, Shaanxi, Sichuan).
Sources
Zheng W, Newcombe G, Hu D, Cao Z, Yu Z, Peng Z (2019) The first record of a North American poplar leaf rust fungus, Melampsora medusae, in China. Forests 10(2), p 182. https://doi.org/10.3390/f10020182