Podosphaera aucupariaePodosphaera aucupariae is a species of powdery mildew in the family Erysiphaceae. It is found in North America and Europe, where it affects rowans/mountain-ashes and service-tree.DescriptionThe fungus forms thin, white irregular patches on the leaves of its host. It is the only species on Sorbus. On Aria, Podosphaera niesslii can also be found, so care should be taken to identify.TaxonomyThe fungus was formally described in 1886 by Eriksson.