A survey of wildflower farms in the south-west of Western Australia for Phytophthora spp. associated with root rots

A survey of wildflower farms in the south west of Western Australia, was conducted during spring of 1997 and autumn 1998 to determine the prevalence of Phytophthora infestations. Thirty-seven randomly selected farms ranging in size from 0.5 to greater than or equal to 30 ha were visited. The main crop plants grown included species of Banksia, Boronia, Chamelaucium, Conospermum, Eucalyptus, Protea, and Leucadendron. Eighteen sites were found to have infestations of Phytophthora. Of these, 14 sites had I? cinnamomi, and 2 sites had P. cryptogea. P. cactorum, P. citricola and P. nicotianae were each found at only single locations. One site was found to have both P. cinnamomi and P. cryptogen. Species of Phytophthora were identified morphologically, isozymically, and using species-specific PCR primers. Not every species could be identified by all 3 methods. There was no apparent association between geographical location and the occurrence of Phytophthora spp.