Sixteen streams in middle and eastern Tennessee were surveyed for the sudden oak-death pathogen Phytophthora ramorum 2010-2012. Surveys were conducted in the spring and fall using healthy Rhododendron leaves, and a total of 354 oomycete isolates were recovered. Sequence analysis of the ITS region provisionally identified 151 Phytophthora, 200 Pythium, two Halophytophthora and one Phytopythium. These include six Phytophthora species (P. cryptogea, P. hydropathica, P. irrigata, P. gonapodyides, P. lacustris, P. polonica), members of the P. citricola species complex, five unknown Phytophthora species, 11 Pythium species (P. helicoides, P. diclinum, P. litorale, P. senticosum, P. undulatum, P. vexans, P. citrinum, P. apleroticum, P. chamaihyphon, P. montanum, P. pyrilobum), three unknown Pythium species, Halophytophthora batemanensis, and one Phytopythium isolate. The biology and implications are discussed.
Keywords: Oomycetes; environmental samples; species diversity.