- The introduction of a new powdery mildew disease on Rhus hirta in various parts of Germany (Brandenburg, Rhine- Westphalia, Sachsen-Anhalt and Saxony) is reported. The anamorph found on this host agrees well with the North American Podosphaera pruinosa. Although the teleomorph has not yet been found in Germany and a molecular study has not yet been possible due to the lack of fresh North American material for a comparison, there is little doubt that the European outbreak of the Rhus powdery mildew disease may be referred to as Podosphaera pruinosa. Morphology, taxonomy and distribution of Podosphaera species on Rhus and other hosts of the Anacardiaceae are discussed in detail.
