First report of the blast pathogen, Pyricularia oryzae, on Eragrostis tef in the United States.
Eragrostis tef, commonly known as "teff," is a warm season crop grown primarily in the western USA for its versatile, gluten-free grain and has recently been gaining wider popularity as a summer forage and as a groundcover for weed exclusion. In late July 2019, leaf lesions, 3 to 6 mm in diameter, with light-colored centers and dark, purple-red edges were observed on leaves of flowering teff plants (cv. 'Dessie') grown as a summer cover at the University of Kentucky Research Farm in Lexington, Kentucky, USA. Following rainfall, the symptoms rapidly progressed to plant death, with 50 to 60% of plants in an area of a few hundred square feet being affected. Diseased plants were collected for pathogen isolation and identification. Based on morphological characteristics, pathogenicity and phylogenomic analysis, the causal agent was identified as Pyricularia oryzae. This is thought to be the first report of P. oryzae on E. tef in the USA.