About Podosphaera physocarpi (U.Braun) U.Braun
This fungus, Podosphaera physocarpi, produces a chalky coating that covers the leaves of its host plant. This coating frequently causes significant distortion to affected leaves and stems, and distortion can extend to entire shoots and inflorescences. It is the only powdery mildew species that occurs on its host, and like many members of the Erysiphaceae family, it only infects plants belonging to a single genus.