Phytophthora dieback is caused by the plant pathogen, Phytophthora cinnamomi, which kills susceptible plants, such as banksias, jarrah and grass trees, by attacking their root systems.
Dieback is a symptom of a Phytophthora infection, and affects more than 40 per cent of the native plant species and half of the endangered ones in the south-west of Western Australia.
The plants die because they cannot take up the water and nutrients they need.
It's is not easy to detect as infected plants often appear to be dying from drought.
There is no known cure for the disease.
Phytophthora disease also affects many agricultural crops and garden plants.
The fungus is spread through the movement of soil and mud, especially by vehicles and footwear. It also moves in free water and via root-to root contact between plants.
It can devastate bushland by removing particular plants and changing the nature of the landscape, possibly driving rare species toward extinction. Changes in the composition of bushland also represent habitat change to animal communities with flow-on effects to their survival potential.
There are several species of Phytophthora, but Phytophthora cinnamomi is the most widespread and destructive. It was probably introduced by early European settlers in the soil of plants they brought with them.
More than 40 per cent of Western Australian native plants are susceptible to the disease, particularly those in state's south-west.
The area of land infected in Western Australia by Phytophthora dieback is equivalent to 500 times the size of Rottnest Island or over one million hectares.
extinctions of threatened plant and animal species that rely on susceptible plants for food and habitat, such as dibblers, western ground parrots and honey possums.
reduced variety of native plants
loss of key understorey species
disruption to woodland vegetation structure
the increased dominance of resistant plants such as grasses, rushes and sedges, or introduced weeds.
Phytophthora cinnamomi lives in soil and in plant tissue, and can survive in plant roots during the dry summer months.
The warm moist soils of the state's south-west provide ideal conditions for Phytophthora cinnamomi to produce millions of spores.
The disease is spread through infected soil and mud, especially by vehicles and footwear, as well as through water and root- to root contact between plants.
Managing the disease
There is no known cure for Phytophthora dieback.
The department is carrying out research into the fungicide phosphite, a biodegradable fungicide that protects plants against Phytophthora dieback. Phosphite works by boosting the plant's own natural defences, allowing some susceptible plants to survive in Phytophthora dieback infected areas.
Prevention
Prevention is still they key. Limiting the spread of Phytophthora dieback is cheaper and far more effective than managing the impacts of the disease once introduced to a bushland.
Phytophthora dieback is most rapidly spread through human activity resulting in the movement of infected soil on vehicles, equipment and footwear.
Forestry and mining industries, as well as recreational bushland users (such as off-road vehicles, mountain bikes and bush walkers) need to take particular care not to spread the disease.
Management practices to prevent the spread of Phytophthora dieback into uninfected areas include strict hygiene measures such as:
cleaning stations to avoid transport of contaminated soil
cleaning footwear and washing down vehicles and equipment
be prepared for and observe restrictions on access.
The department's role
Phytophthora dieback research is a major component of the department's work.
Our research includes:
detecting and identifying new Phytophthora species in Western Australia
monitoring the spread, and rate of spread, of Phytophthora pathogens
investigating the genetic makeup and survival capacity of Phytophthora species
investigating the susceptibility of Western Australian plants to Phytophthora cinnamomi and other Phytophthora species
researching the biology and epidemiology of Phytophthora species in native plant communities
investigating ways to reduce the spread of Phytophthora dieback.
investigating ways to optimise current control methods including phosphite treatment, and hygiene and quarantine protocols
researching the role of fire in managing species susceptible to Phytophthora
translocating plant species at risk. This involves deliberately transferring plants from one area to another to help conserve it.
seed banking rare and endangered flora that is susceptible to Phytophthora disease. Seed banking offers us an efficient and cost effective way of conserving genetic diversity for future conservation work
researching and understanding the long-term impacts of Phytophthora cinnamomi in Western Australian ecosystems.
The department has an active program to detect, diagnose and map the occurrence of dieback on lands managed by Parks and Wildlife. This includes interpreting and mapping areas for Phytophthora dieback prior to disturbance operations to manage or contain the spread of dieback. Visit the department's Vegetation Health Service to identify and detect Phytophthora species.
Management of Phytophthora disease (Policy 3)228.81 KB
