Occurrence of powdery mildew caused by Erysiphe paeoniae on Paeonia suffruticosa

Abstract

Since 2013, Paeonia suffruticosa (tree peony) shrubs in Korea have been found to be infected with powdery mildew. Phylogenetic analyses based on both ITS rDNA sequences and the morphological characters of the anamorph and teleomorph stages determined the powdery mildew to be Erysiphe paeoniae. This is the first case of E. paeoniae infection on a host plant in sect. Moutan of the genus Paeonia, and is the first report of powdery mildew occurring on P. suffruticosa worldwide. The occurrence of powdery mildew is a potential threat to the widespread ornamental plantings of P. suffruticosa. Information about the morphological and genetic characteristics of this disease may help Paeonia breeders, growers, and gardeners to monitor the disease.