fīˈtäfthərə noun
Etymology: New Latin, from phyt- + -phthora
1. capitalized : a genus of destructive parasitic fungi (family Pythiaceae) having conidia that usually act as sporangia especially under moist cool conditions and sporangiophores that are simple or branched — see late blight , pythiacystis
2. -s
a. : any fungus of the genus Phytophthora
b. : a disease (as late blight) caused by such a fungus