Phytophthora cinnamomi (Phytophthora dieback).

P. cinnamomi is a soilborne pathogen that is now widely established in many parts of the world. Initial long-range spread is likely to have been on infected nursery plants (e.g., Kenerley and Bruck, 1983; Benson and Campbell, 1985; Davison et al., 2006), and still occurs in this way. Additional long-range spread is by movement of soil and gravel infested with chlamydospores (e.g., Batini, 1977; Colquhoun and Petersen, 1994). Short-range spread is also by zoospores in drainage, seepage and irrigation water (Kinal et al., 1993; MacDonald et al., 1994). It has a very wide host range (Zentmyer, 1980) so that, once introduced into an area, it can persist on the roots of many different plants without necessarily causing symptoms on the foliage. It is a major pathogen of horticultural crops, in forestry and in natural vegetation, especially in southern Australia (Natural Resource Management Western Australia, 2013 - see http://www.dieback.net.au/pages/1382/susceptible-species). It is regarded as a key threatening process in the Australian environment (Environment Protection and Biodiversity Conservation Act, 1999), affecting both plant communities by reducing diversity, and the animal communities that depend on them. It is considered by ISSG (2012) to be one of the 100 worst invasive species worldwide.