Further details on Puccinia hemerocallidis
In the US, Puccinia hemerocallidis (EPPO Alert List) was first found in Georgia in 2000, and later spread to more than 20 states (including Hawaii). This fungus originates from Russia (Siberia)* and also occurs in China (Manchuria), Japan, Korea and Taiwan. Initial observations on uredinospore morphology and the presence of teliospores suggested that the American fungus may be different from the Asian species, and research was carried out to investigate this. The type specimen from Russia (Western Siberia, 1878) was examined and compared with specimens from China, Costa Rica** (specimen intercepted in USA), Japan, Russia (Primorski territory)*, Taiwan (Taihoku province) and USA. Based on morphological studies and molecular analysis of the ITS region, it was concluded that the American and Asian specimens belong to the same species. The authors note that Hemerocallis is one of the most important cultivated perennial plants in the US. There are currently extensive exchanges of Hemerocallis with other American countries, since plants from US are shipped to Costa Rica and other Central American countries to be propagated during the North American winter. This may have favoured spread.
*The EPPO Secretariat previously had no clear indication of the presence of this fungus in Russia.
**There is suspicion that the fungus could also be present in Costa Rica, as symptomatic plants from this country have been intercepted by USA, but this has not been confirmed.
Sources
Hernandez, J.R.; Palm M.E.; Castlebury, L.A. (2002) Puccinia hemerocallidis, cause of daylily rust, a newly introduced disease in the Americas.
Plant Disease, 86(11), 1194-1198.