Puccinia subnitens: An Obscure Rust Pathogen Little-Known for More than a Century

Abstract

Sugar beet seedling rust, caused by Puccinia subnitens, is a rarely occurring but essentially harmless disease in sugar beet production. However, it has caused substantial but sporadic losses to commercial spinach growers. It has the typically complex life cycle of a macrocyclic rust pathogen, but is also unusual because it is one of the few documented heteroecious rust diseases where the early spore stages (pycnial and aecial) occur on the economic host while the normally damaging, repeating, uredial stage is found on the feral, noneconomic host. Most significantly, it was one of the first heteroecious rust diseases recognized to have the ability to infect numerous, distinct host species with the aecial stage while maintaining a relatively narrow host range for its uredial and telial stages. Accepted 6 June 2014. Published 25 July 2014.