Phytophthora multivora  Phytophthora multivora is a species of Oomycete, water moulds, identified as a plant pathogen implicated in dieback. It was first isolated in tuart forest of Southwest Australia in a study of the decline of tuart "Eucalyptus gomphocephala", jarrah "Eucalyptus marginata", peppermint "Agonis" and banksia species. The species was found to occur in dead and dying woody species, "Eucalyptus gomphocephala", "E. marginata", "Agonis flexuosa", banksias "B. menziesii" and "B. grandis" and at the fine roots of "E. marginata" and "Banksia littoralis". The study area included samples at Yalgorup, Jarrahdale, Wanneroo, Walpole and Pemberton in Western Australia. The epithet of the species is in reference to the wide range of flora it infects.