The Collaborative International Dictionary of English v.0.48:
Peronospora \Peronospora\ prop. n. A genus of destructive downy mildews. Syn: genus Peronospora. [WordNet 1.5]WordNet (r) 3.0 (2006):
Peronospora n 1: genus of destructive downy mildews [syn: Peronospora, genus Peronospora]