1. How do I know if I have dieback?
The presence of Phytophthora dieback is determined by observing deaths in plants that are considered susceptible to the disease. 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 following vegetation features can also be used to indicate the presence of Phytophthora dieback.
- Plant deaths localised within a distinct location of the property, usually a low lying, water accumulating area. Lines, groups or localised areas of plant deaths are more likely to be caused by Phytophthora dieback than odd scattered individual plant deaths in otherwise healthy vegetation.
- Look for an edge effect. Edge effects are most obvious when there is a clear distinction between healthy and diseased vegetation.
- Look for old deaths and recently killed plants, that is, an 'age range' in the deaths. This is because Phytophthora dieback moves from plant to plant over time, killing each plant as it goes.
- Look for signs of the disease in a range of different susceptible plant species.
- Look for something that could have introduced the disease, for example, a track, road or vehicle activity.
You must be careful to discount other factors that could have caused plant deaths, such as fire, insects, flood, drought, nutrient deficiencies or toxicities, herbicide damage; and other plant diseases. If non-susceptible trees, for example red gums, tuarts, flooded gums or wandoo are dying then it is likely that the cause of poor plant health is not Phytophthora dieback.
2. How do I manage dieback on my property?
To manage Phytophthora dieback in bushland on your property you need to avoid its introduction, minimise its spread over your property if present and treat infested areas with phosphite. For a property with a significant area of bushland, the first step to successfully managing the disease is to know where it is and where it isn't. Getting good advice at this stage from either a consultant, your local catchment group, your local government authority or the Dieback Working Group will not only save you time & money, but optimise your success. Land owners in high risk areas who currently have a disease-free property should take all practical steps to prevent the accidental introduction of the disease. For further information on how manage the disease within private property and bushland please refer to our Bushland Manual, found in our publications section.
3. How can I get advice or receive training on phosphite treatment?
You can receive training on Phytophthora dieback management and phosphite treatment by contacting your local community based conservation group, catchment group or the Dieback Working Group.
4. What plants do I inject and which plants do I spray?
In bushland the most common tree species injected include jarrah, snotty gobbles, banksia species, sheoak and woody pears. Only inject trees with a diameter at chest height of 10-14 cm or greater.
To complete the treatment spray all other plants including small trees and understorey species such as Grass trees.
5. Where do I start?
Identify where the Phytophthora dieback is in the bushland area and as a priority treat the buffer between healthy and diseased vegetation to prevent the movement of the disease into the healthy area. Once complete you can then treat along edges of tracks, paths and within the diseased area.
6. How often do I need to treat?
You will need to repeat phosphite treatment to maintain the control of the disease. Injecting needs to be conducted very 3-5 years and spraying every 1-2 years.
7. What personal protective clothing should I wear?
Make sure to always wear old clothing or overalls, gloves, safely glasses and a face mask when spraying. Likewise make sure to wear old clothing or overalls, gloves and safely glasses when injecting. For further information on first aid treatment please consult the material safety data sheet supplied with the chemical.
8. Where can I get equipment & chemicals?
Phosphite treatment gear can be purchased from Dieback Treatment Services. Alternatively a number of community groups across the south-west hire out the treatment gear, contact the Dieback Working Group for more information.
Phosphite and surfactants/penetrants can be purchased from Agricultural supply companies such as Mirco Bro's or Landmark Operations.