The arrival and spread of dieback disease (caused by the root-rot fungus Phytophthora spp.) in Western Australia has been catastrophic for the biota of a number of south-west Australian ecosystems. There are several species of Phytophthora present in native vegetation in the south-west of Western Australia, but by far the most widespread and destructive is Phytophthora cinnamomi, thought to have been introduced soon after European settlement. As many as 2,000 of the estimated 9,000 native plant species in the south-west are susceptible to and often killed by dieback disease.

Photo showing the effects of dieaback in Stirling Range National Park