Leaf spot of barnyardgrass caused by Exserohilum oryzicola in Japan and the fungal influence on rice, barley, bread wheat, durum wheat, and soybean

Brown lesions were found on leaves of the weed barnyardgrass in paddy fields in Hiroshima Prefecture in western Japan in June 2017. A fungus, isolated repeatedly from diseased plants and identified as Exserohilum oryzicola , was demonstrated to be pathogenic to barnyardgrass. The disease was diagnosed as leaf spot, reported abroad but new to Japan. In pathogenicity tests, the isolate was also pathogenic to barley, bread wheat, durum wheat, and rice but foliar symptoms were milder than on barnyardgrass; it was nonpathogenic on soybean.