PHYTOPHTHORA IN AUSTRALIA

Phytophthora spp. are one of Australia's most serious plant pathogens, causing well in excess of $200 million in lost production annually ac ross all of our plant-based industries. Of the more than 50 species of Phytophthora recorded worldwide, over 20 are present in Australia. Al l species, along with their hosts, distribution and current control me asures have been tabulated. Use of molecular markers to analyse popula tion genetic structure has shown that most of these pathogens have bee n introduced from overseas, and become widely distributed in Australia within relatively short periods of time. The review highlights the ge neral biology of Phytophthora spp. and their impact on agricultural pr oduction in Australia, with particular emphasis on the genetics of hos t/pathogen interactions, population genetic structure and reproduction of Phytophthora populations in Australia. The review highlights the r ole molecular technologies may play in developing an understanding of host-pathogen recognition and pathogenesis in Phytophthora. Three case histories, involving P. sojae, P. medicaginis and P. cinnamomi, have been developed to provide insights into current levels of understandin g, and to identify gaps in our knowledge. Current control measures are summarized and possible new avenues of control discussed.