The rust has never been previously described on daylilies in the United States, and was first identified in Georgia in August 2000. It currently has been identified in Georgia, Florida, Alabama and South Carolina.
Daylily rust is caused by the fungus Puccinia hemerocallidis.
There is some uncertainty over the species designation of the fungus because there are differences in spore morphology from specimens obtained from Georgia and those obtained from Florida. However, the rust seen on daylily samples in Georgia appears to be P. hemerocallidis. Daylily plant material is commonly shipped into the United States from Costa Rica, Guatemala, Honduras, Mexico, Bahamas, South Africa, and the Netherlands. However, most of the daylilies produced in these countries, in particular from Central America, originate from the United States. Therefore, the origin of the daylily rust is unknown.