First Report of Rust on Perennial Ryegrass Caused by Puccinia coronata in Jiangsu, China

Abstract

Perennial ryegrass (Lolium perenne L.) is primarily used to overseed dormant warm-season lawns in transitional zones of China. In May of 2017, a high incidence of foliar rust was observed throughout perennial ryegrass swards established at the campus of Nanjing Agricultural University and caused lesions covering 10% to nearly 100% of total leaf tissue. Uredinia pustules on infected leaves were brownish yellow to yellow and in linear streaks along host veins. Uredinia were orange and observed on the adaxial surface of the leaf blade at the early stages of disease, as the disease progressed, uredinia developed on the abaxial surface. Urediniospores were globose to broadly ellipsoid, had 4-7 scattered germ pores and were 22.0-28.7×17.8-23.2 μm with a wall that was dark brown and 1.8-2.8 μm thick. No teliospores were observed. The morphology of urediniospores was similar to Puccinia coronata Corda described previously (Cummins 1971). The pustule phenotype on the infected leaves and host association with peren...