- Plants for gardens
- Wollemi pine
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- Pests & diseases
- Phytophthora Dieback
- Plant Disease Diagnostic Service
- Fact Sheets
- Identifying plants
4. Brochures, fact sheets & poster
The text and images on the brochures and fact sheets are displayed here, one after the other so you can read and/or print the information all at once, or you can click an image of a brochure or fact sheet to save or print the PDF version.
Newly developed material
The Royal Botanic Gardens & Domain Trust
See Research & Education Projects for links to Hawkesbury-Nepean and Sydney Metro CMA websites for Best Practice Management Guidelines for Phytophthora cinnamomi.
1. How to stop the spread: are you a carrier?
This leaflet explains how Phytophthora Dieback is spread and the simple actions required to halt the spread.
Are you a carrier? Phytophthora Dieback is a silent plant killer.
Phytophthora (pronounced fy-TOFF-thora) is a devastating plant killer. It attacks and rots plant roots, destroying the food and shelter of many animals. It is a water mould which spreads naturally in water or roots. It is spread much faster and further by humans moving contaminated soil or plant material, even small amounts.
When you’re in the bush, please take care not to spread this devastating disease.
Phytophthora Dieback is threatening susceptible plant species, such as the NSW state floral emblem, the Waratah (Telopea speciosissima) which is an abundant source of food for native wildlife.
Protect Australia’s unique plants and the fauna that depend on them. Gang Gang Cockatoos (Callocephalon fimbriatum) feed mainly on seeds, preferring eucalypts and wattles, and they require tall trees for nest hollows. Phytophthora Dieback kills their food and shelter.
Don't be a carrier
Not only your shoes! Soil sticks on anything that touches the ground: backpacks, walking sticks, tent pegs and of course off-road bikes and car tyres, and even clothing while you’re sitting!
So dust yourself off and discard any mud or soil as you go.
Disinfecting is easy if you spray with 70% methylated spirits diluted with water.
2. Managing Phytophthora Dieback in bushland
Our brochure summarises the five strategies approach we have developed to manage Phytophthora Dieback in bushland.
Stamp out the spread of Phytophthora Dieback
Phytophthora (pronounced fy-TOFF-thora) is a silent killer in our midst with the potential to have devastating impacts on ecosystems. It is a water mould that survives in water, soil and plant roots and kills plants by attacking and rotting their roots.
Use this five strategies approach to manage Phytophthora Dieback in your bushland.
This disease kills plants and infection is permanent. We can help by
Phytophthora is spread naturally in water and via infected roots, and faster and further by humans moving contaminated soil or plant material. It can remain dormant for long periods during dry weather and is virtually impossible to remove from infected areas.
So limit its spread by managing water and soil movement.
Phytophthora Dieback attacks many native plants and it also has the potential to have a significant impact on nursery, horticulture, floriculture, tourism, mining and forestry industries. This killer can also impact on native animals, including marsupials, birds, reptiles and insects, by reducing or eliminating vegetation they rely on for survival.
1. Understand Phytophthora Dieback
Phytophthora Dieback attacks plants where you can’t see it occurring, at the roots. It travels in water and along root systems and is spread in contaminated soil. What you can see above ground is
Even plants that are not highly susceptible will succumb during long periods of dry weather. The loss of root mass limits the amount of water and nutrients a plant can absorb, leaving it susceptible to insect attack, plant diseases and drought stress. The spores of Phytophthora can persist indefinitely in an area protected in the roots of plants, even those that are not susceptible to Phytophthora Dieback. Disease depends on three essential components: plant host, environment and the pathogen. Phytophthora occurs in areas with rainfall greater than 500 mm per annum. It is most active when the soil is moist and warm. It can also survive for long periods in plant tissue and soil during dry soil conditions.
Favourable soil conditions for the disease are
The only effective ways to combat Phytophthora Dieback are by
Assess the risk of disease for the site and use data from the assessment to set up an appropriate management plan. Include a site monitoring program and routines to evaluate effectiveness.
* Click here for a list of resistant and susceptible native plants.
2. Assess for risk of disease
Record data from the site assessment in a way that it can be used to monitor changes in vegetation over time. Assess the risk on a yearly cycle.
a) Define climatic risk
b) Gather information and quantify risk
c) Soil sampling
Sampling soil for laboratory analysis
d) Develop a reassessment and monitoring program
3. Adjust work practices to reflect risk
Human activities cause the most significant, rapid and widespread distribution of Phytophthora Dieback. Any activity that moves soil, water or plant material, or alters the natural movement of water, could spread the disease. Soil can be moved inadvertently or deliberately.
Examples of inadvertent movement of soil or plant material during work or recreation are by
Work activities likely to create movement of soil, water and plant material include
Prevent introduction and minimise the spread to unaffected areas by controlling the movement of soil, plant material and water by
4. Inform all staff, contractors & visitors
5. Treat infections
Attempts to eradicate Phytophthora from infected areas have largely been unsuccessful. Treating with the fungicide Phosphonate (Phosphite) boosts the plant’s natural defences and research has shown that it increases the resistance of susceptible plants to Phytophthora Dieback but it does not kill the pathogen. Infected plants remain a reservoir of the pathogen, even after they die. Treatments with Phosphonate are most effective during the active growth months, generally spring and summer. This fungicide is manufactured by a number of companies and is widely available. Spraying provides one to two years protection. Spray when at least two rain-free days are forecast and there is little or no wind.
Keep mixture well mixed while spraying, soaking the plants and ensuring all surfaces are wet.
You may need to apply for a permit for off-label use of the fungicide.
There are only three management objectives for Phytophthora Dieback
Contacts and further information
The following web sites have information on susceptible and resistant plants, and details on how to assess your site for Phytophthora, alter work practices and apply treatments.
For more information please contact
Plant Disease Diagnostic Unit
3. 'Don’t let us die' poster
A poster was developed in 2010 as part of the Environmental Trust Dissemination Grant. Print the poster and display in your visitor centres, work areas, or recreational meeting places to remind people of the need to consider the spread of Phytophthora Dieback in their activities.
4. Facts about Phytophthora
What is Phytophthora?
Phytophthora (pronounced Fy-toff-thora) is a microscopic organism that lives in soil and plant roots. The name Phytophthora is derived from the Greek meaning ‘plant destroyer’. Phytophthora causes root rot in a broad range of plant species, including many native Australian and ornamental plants. Around 60 Phytophthora species have been identified, but P. cinnamomi is the species that is most destructive in native Australian vegetation communities.
How does Phytophthora affect plants?
P. cinnamomi attacks the roots and stems of plants, destroying the root system and reducing the ability of the plant to absorb water and nutrients. In susceptible plants, the young roots become dark and rot.
Above ground, symptoms include wilting, yellowing and retention of dried foliage. Infection may result in the death of the plant. Symptoms are often more severe, and death more rapid, when plants are suffering from water stress (e.g. in summer or drought).
Is Phytophthora a problem in NSW?
The extent of the occurrence of Phytophthora in NSW is only beginning to emerge, but the pathogen appears to be more widespread than originally thought. It has been identified in the World Heritage areas of northern NSW, including Barrington Tops NP, the Blue Mountains, including Wollemi NP, in southern NSW near Eden and in bushland reserves around Sydney Harbour.
How is Phytophthora spread?
Phytophthora lives in soil and plant material. Any movement of infested soil or plants can spread the disease.
This includes soil on tools, footwear and vehicles. Phytophthora reproduces very quickly by producing millions of motile zoospores, particularly when the soil is moist and warm. The zoospores can be easily transported in drainage water, especially down slope. When conditions become less favourable, Phytophthora produces resistant chlamydospores, which enable it to survive until conditions become conducive again.
Which plants are affected?
Phytophthora cinnamomi threatens the biodiversity of natural ecosystems. The pathogen is known to infect banksias, native peas, eucalypts and ornamentals such as rhododendrons and camellias. It also impacts on native fauna by destroying food sources and habitat.
How can I manage Phytophthora?
It is impossible to eradicate Phytophthora from infested areas so limiting further spread is critical to management efforts. You can reduce the chances of spreading the disease by
If you think you may have dieback you can have your soil tested for the presence of Phytophthora.
What is the Royal Botanic Gardens & Domain Trust doing?
In order to effectively manage the disease it is essential to understand where Phytophthora occurs. Staff Sydney's Botanic Gardens are surveying the occurrence and distribution of the pathogen. The location of Phytophthora will be mapped and information collected will be used to develop and implement management guidelines. For more information please contact:
Plant Disease Diagnostic Unit
5. Phytophthora root rot - fact sheet
Phytophthora cinnamomi is a microscopic soilborne organism, invisible to the naked eye, which causes root rot of a wide variety of plant species including many native and introduced plants. Other species of Phytophthora may cause diseases on a wide range of plants but are generally less severe. The biology and control measures are very similar so this outline will concentrate only on Phytophthora cinnamomi.
Infection often results in the death of the plant, with earlier symptoms including wilting, yellowing and retention of dried foliage and darkening of young feeder roots and occasionally the larger roots. Phytophthora cinnamomi requires moist soil conditions and warm temperatures to be active, but damage caused by the disease most often occurs in summer when plants are drought stressed. The plant is unable to adequately absorb enough water from the soil because its roots are damaged and consequently may die. Small swimming zoospores are released which attach to and infect roots, normally behind the root tip. All spores and structures of Phytophthora are microscopic and cannot be seen with the naked eye. There is no way of visually telling if the pathogen is present in the soil.
After infection Phytophthora grows through the root destroying the tissue which is then unable to absorb water and nutrients. Further zoospores are produced in sporangia, particularly when the soil is moist and warm, and are released into the soil. Consequently zoospore numbers can build up quite rapidly. Zoospores move in water and may infect neighbouring plants especially those down slope from a site of infection. These spores are easily transported in storm water, drainage water, contaminated soil and on tools, footwear and vehicles. A further two spore types may be produced, a chlamydospore and an oospore, which are survival structures produced when conditions become unfavourable such as when a food source is exhausted or in periods of low temperature or drought. These spores are capable of surviving for extended periods of time, and when conditions become favourable they germinate and renew the life cycle. This allows Phytophthora to survive in dead plant tissue and in the soil for extended periods.
At present there is no one simple method for controlling Phytophthora cinnamomi. A combination of sanitation measures, good horticultural management, selective use of some fungicides and the addition of organic matter to soils can be used to retard the activity of Phytophthora.
Nursery: All plants should, wherever possible, be grown in soil mixes which have been correctly steam-air pasteurised (30 minutes at 60ºC). If it is not possible to pasteurise mixes make sure that the mix components are disease free. Ensure that the potting mix is not subsequently contaminated. eg. by water draining into soil bins in heavy rain or by careless handling with implements. Plants brought into nurseries from outside sources should ideally be propagated by cuttings to prevent the importation of Phytophthora (and many other disease and insect pests), or quarantined. All previously used pots and containers should be free of soil prior to use and sterilised by soaking in a solution of a disinfectant/detergent compound. It is essential to remove soil by washing prior to soaking in order to achieve maximum kill of the pathogen. It is also important to wash implements (cutting knives, secateurs etc.) regularly to remove any possibility of transferring the fungus from one plant to another. Avoid bringing contaminated soil on boots and equipment into the nursery areas. Phytophthora cinnamomi can survive in very small quantities of soil for long periods of time so nursery sanitation is very important. All plants should preferably be grown on raised wire-mesh bench at least 30 cm off the ground; this minimises water splash, which may possibly contain the fungal spores, from the ground onto the plants. If this cannot be achieved plants should be grown on free draining blue metal. Keep the whole nursery area clean and free of dead plant material and refuse. Soil mixes should permit free drainage; a potting mix which allows air into 15% of air spaces after watering is recommended. If a plant becomes infected, or is suspected of being infected, if possible it should be carefully examined (without contaminating other plants) for symptoms such as darkening of young rootlets. Infected and dead plants should be removed and disposed of carefully. Burning the infected plant or disposal in garbage are the most satisfactory methods of disposal. Infested potting soil should be carefully disposed.
Hygiene: Sanitation of tools, machinery and boots is probably the most effective means by which the spread of Phytophthora cinnamomi can be limited. Spades and other tools should always be washed free of soil before and between plantings. In addition, tools should be regularly drenched in a solution of detergent or disinfectant. A large drum containing this solution should be placed in a convenient place in the depot and tools should be regularly brought back, washed to remove soil and drenched. The more frequently this is done the better the control of any soilborne diseases, particularly Phytophthora, will be. In situations where you are planting a number of plants take a container of disinfectant with you and disinfect tools between replanting. Boots and tyres are also an important means by which Phytophthora may be transported, as soil containing the fungus may cling to the boot or tyre. Wherever possible remove soil from boots and tyres and limit the movement of soil and the fungus. Vehicles should move towards known infected areas and be washed down after working in these areas before use in clean areas. It may not always be feasible to remove all soil, however limiting the movement of large amounts of soil by washing off with water will suffice in most situations. Sanitation procedures may seem time consuming and annoying, but prevention and limitation of a disease such as Phytophthora is the most effective means of disease control.
Soil preparation: Regardless of whether the pathogen is present in a soil it is important to add quantities of organic matter such as mulches, manures and composted material to the area (if this is appropriate to the plant species). These components increase the level of soil micro-organisms, such as fungi (eg. Trichoderma), actinomycetes and bacteria, which suppress the activity of Phytophthora and retard disease development. Mulches also minimise the contact between soil and footwear so that there is less potential for the transport of soil. Maintain nutrient levels so that root growth is promoted, but however do not use inappropriate nutrient mixtures that may be deleterious to the plant (ie. take care with phosphate sensitive plants). If possible, plant in holes sufficiently large enough to promote rapid root growth, this combined with good nutrition will allow the plant to compensate for any root damage caused by pathogens. Never use techniques such as post-hole diggers to prepare planting holes as these techniques result in poor drainage, thus enhancing disease development, and may aid in the spread of the pathogen. Ensure that drainage is adequate to prevent water logging, which promotes disease incidence and severity. All run-off water from known infected sites should be contained and directed to the storm water channels. Remember that water can very easily transport the swimming zoospores of Phytophthora cinnamomi.
Prevention and caring of infected plants: Fungicides containing potassium phosphonate are registered for control of this disease in certain situations. Information on these fungicides can be obtained from your local nursery or on the websites of the manufacturers. It is however important to ensure that application occurs when the plant can be expected to be actively exporting from the leaves to the root system ie. in summer (once in early summer and then 4-5 weeks later), so that the chemical is transported to the roots where it is required. Plants should be sprayed for quite a wide area around the infected site. If you have to move or replant material never move a plant from an infected site to an uninfected site. If the species is required in these circumstances, repropagate by cuttings. As in the case of initial plantings, the preparation of the site, the addition of organic matter and the attention to drainage are all essential when replanting material. When removing plants it is essential to remove as much of the tissue, including roots, as possible. The pathogen may persist in dead tissue for many years. Dead roots and any pruned material should be disposed of carefully. Do not replant in the same plant hole; where possible plant away from the dead plant, preferably upslope as plants downslope from any site of infection will be at greatest risk from the disease. Remember that unassisted movement of Phytophthora up a slope is very slow, while downward movement may be quite rapid.
Plant Disease Diagnostic Unit