Origin: Far East
First finding in Slovenia: before 2010
Pathways: likely transported with fruits; secondary spontaneous spreading
Possible to identify: June-October
Habitat: Common on Alnus incana, more rarely on Alnus glutinosa.
Status in Slovenia: Currently spreading, the severity of the infection differs from year to year, depending on the weather (high humidity increases infection pressure).
Similar species: Melampsoridium alni, M. betulinum & M. carpini.