Puccinia modiolae in North America: distribution and natural host range

Abstract

Puccinia modiolae, a rust fungus pathogen of Carolina bristlemallow, Modiola caroliniana (Malvaceae), is newly reported from North America, appears to be well established along the Gulf coast and is likely to have been introduced from South America. Its taxonomy, distribution and natural host range are discussed and a lectotype designated for this species. Malva sylvestris and Alcea rosea are reported as new hosts for the rust. Additional new records for Malvaceae rusts are made for P. modiolae on Alcea rosea from Brazil, P. heterospora on Herissantia crispa in Florida and P. heterogenea on Malva sp. in Peru. Finally, an identification key for the microcyclic Puccinia species on members of Malvaceae in North America is provided.