Downy Mildew of Shepherd’s Purse Caused by Hyaloperonospora parasitica in Japan

Abstract

In April 2015, irregularly and yellowing lesions on the leaves of shepherd’s purse (Capsella bursa-pastoris) were found in an outdoor field in the south area of Ibaraki Prefecture. White and powdery stigmata of this pathogen were observed on the lesions. The pathogen of this disease was identified as Hyaloperonospora parasitica based on the morphological features of conidia and conidiophores, host range and the sequence of ribosomal DNA internal transcribed spacer (rDNA-ITS) region.