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dieback_imgPhytophthora dieback refers to the deadly introduced plant disease caused by Phytophthora cinnamomi (pronounced Fy-tof-thora – meaning plant destroyer in Greek). There are over 50 species of Phytophthora, but the species that causes the most severe and widespread damage to native plants in Western Australia is P. cinnamomi. Common susceptible plants include Jarrah, banksia, grass-trees, zamia palms, dryandra and hakea species. Arguably the best indicator species for Phytophthora dieback in WA are the Banksia species. The presence of Phytopthora Dieback can be indicated by the decline in health or death of the species listed above. Over 40% of plant species in South West WA are susceptible to Phytophthora Dieback. Phytophthora Dieback can also affect home gardens and agricultural crops (such as avocado’s and grapes) and is introduced with infested soil, mulch, gravel and diseased plants.

In the past, Phytophthora dieback has been known as ‘dieback’ and ‘jarrah dieback’. Unfortunately, these names have contributed to confusion about the pathogen. For example, in other parts of Australia, the term ‘dieback’ is used to describe tree decline caused by such factors as salinity, drought or insect damage. Furthermore, the disease affects a huge number of introduced and native plant species other than jarrah. Therefore, to overcome this confusion, the term ‘Phytophthora dieback’ is now used.

Phytophthora dieback spends its entire life in the soil and in plant tissue. It causes root rot in susceptible plants, thereby limiting or stopping the uptake of water and nutrients. The pathogen is able to survive within plant roots during the dry soil conditions commonly experienced during the summer months. (Reproduced from the Dieback working group website 2012

Please visit for more information on Phytophthora Dieback.

For more information on Phytophthora Dieback in the Geographe Catchment please visit our Dieback Management Project Page.