Occurrence of leaf blast on white oats, Italian ryegrass and wheat in Southern Brazil

Abstract

Fungi of the genus Pyricularia are widely known to cause rice blast and have also infected other commercially important grasses such as forage, wheat and oats. In Brazil, wheat blast was initially identified in northern Paraná in 1985 (1), affecting black oats in 2006 (4), white oats in 2012 (3) and Italian ryegrass in 2001 in Rio Grande do Sul State (5). At the experimental area of Federal University of Pampa, Itaqui Campus, Rio Grande do Sul State, Brazil, located at 29° 09’19.9”S and 56° 33›16.9» W, on 08/08/2019, plants of Lolium multiflorum Lam. (weed and cultivar ‘Barjumbo’), Avena sativa L. (cultivar ‘IP Esmeralda’), and Triticum aestivum L. (cultivar ‘BRS Tarumã’) were found to have characteristic leaf blast symptoms, which included elliptical to elongate lesions showing white to light brown centers and dark grey to reddish-brown borders (1, 2). Plants with symptoms of blast were collected and prepared for the humid chamber. Leaf regions with these symptoms were sectioned and disinfected in 1% sodium hypochlorite for three minutes, followed by washing with water. Then,