What is "phytophthora"

n. Any of many parasitic fungus, of the genus (taxlink Phytophthora genus noshow=1), that cause brown rot in plants.

Phytophthora (from Greek φυτόν (phytón), “plant” and φθορά (phthorá), “destruction”; “the plant-destroyer”) is a genus of plant-damaging Oomycetes (water molds), whose member species are capable of causing enormous economic losses on crops worldwide, as well as environmental damage in natural ecosystems. The cell wall of'' Phytophthora'' is made up of cellulose. The genus was first described by Heinrich Anton de Bary in 1875. Approximately 100 species have been described, although 100–500 undiscovered Phytophthora species are estimated to exist.