Microsphaera
/ˈmʌɪkrə(ʊ)ˌsfɪərə/noun
A genus of plant-parasitic fungi (family Erysiphaceae) that includes the causative agents of European gooseberry mildew, oak mildew, and various other powdery mildews.
Origin
Late 19th century; earliest use found in Mordecai Cooke (1825–1914), naturalist and mycologist. From French microsphaera from micro- + classical Latin sphaera.