Peronosporaceae are a family of water moulds that contains 17 genera, comprising more than 600 species. Most of them are called downy mildews. The closest relative of Peronosporaceae's Phytophthora. Peronosporaceae are obligate biotrophic plant pathogens. They parasitize their host plants as an intercellular mycelium using haustoria to penetrate the host cells. The downy mildews reproduce asexually by releasing sporangia or conidia. These may collectively be referred to as Conidiosporangia. Sex… (More on Peronosporaceae)