Podosphaera paracurvispora (Erysiphaceae, Ascomycota), a new powdery mildew species on Pyrus from China

Podosphaera paracurvispora, a new powdery mildew species of Podosphaera sect. Podosphaera, is described and illustrated on Pyrus ussuriensis in China. Podosphaera paracurvispora differs from P. clandestina and P. leucotricha which are common causal agents of Pyrus powdery mildew in having crescent-shaped ascospores, and from P. curvispora, endemic in Japan on Sorbus spp., in having much broader pale brown ascospores. The morphological characteristics and phylogenetic analyses strongly suggest that the fungus is a new, undescribed species.