First report of walnut brown spot (anthracnose) caused by Ophiognomonia leptostyla in Japan

Abstract

In 2016, brown spots were found on walnut (Juglans regia L.) leaves and fruits in Nagano Prefecture, Japan. A white to gray fungus was isolated from the brown spot lesions and identified as Ophiognomonia leptostyla (Fr.) Sogonov based on morphological characteristics and rDNA LSU, rDNA ITS and EF-1α sequences. Inoculation of walnut leaves with O. leptostyla caused the same brown spots on the leaves, and the fungus was reisolated from the lesions. This is the first report of walnut brown spot (anthracnose) caused by O. leptostyla in Japan.