Pathogen Identification and Factors Influencing Infection Frequency and Severity of Fungal Rust in Four Native Grasses in Hulunber Grassland, China.

A serious rust infection present in 2014 and 2015 on the dominant grass species () in the Hulunber grassland of Inner Mongolia, China, and also present on three other grass species ( [wheat grass], , and ) was investigated. Field surveys, laboratory determination of morphological characteristics, pathogenicity tests, and molecular identification methods were integrated to identify two rust-causing pathogens on . . It was found that was the major pathogen of . , and also infected . and . . This is the first report of . on . in China. . caused stripe rust on . and . . The incidence and severity of rust infection increased through the growing season, presumably from asexual spread by urediniospores, and was higher on grass species phylogenetically more closely related to common crop hosts of the pathogens. High host grass density and presence of a potential alternate host for , , were two further factors promoting rust incidence. These results provide insight into ecological factors linked to the rust epidemic and provide a theoretical basis for the formulation of control strategies.