phytophthora pluvialis phytophthora pluvialis phytophthora pluvialis is a semi-papillate plant pathogen that mainly infects tanoak-douglas-fir forests of western oregon. it was reported in cornwall. uk, in october 2021; the first record for europe. phytophthora pluvialis scientific classification kingdom: chromista phylum: oomycota order: peronosporales family: peronosporaceae genus: phytophthora species: p. pluvialis binomial name phytophthora pluvialisreeser, sutton & hansen, 2013 description phytophthora pluvialis is homothallic; it forms oogonia in culture. its oogonia are terminal, smooth and globose, being approximately 30 µm in diameter, and possess amphigynous antheridia. its oospores are globose and aplerotic, being about 28 µm in diameter. sporangia formed in water are ovoid and slightly irregular, semi-papillate, terminal or subterminal, and partially caducous with medium-sized pedicels.