Phytophthora cinnamomi is clearly well established in many areas of Tasmania. It is continuing to spread from existing infections with the movement of water, animals and its own mechanisms for movement. Humans have the capacity to spread the fungus long distances and across barriers which sets us apart from the natural mechanisms for spread. There is practically nothing that can be done to control the natural spread of the fungus or to destroy it, in the native plant communities. Such actions are largely limited to the horticultural industry where soil fumigation and control of vectors for spread is possible. A line of research under investigation in Australia at present is the application of fungicides to increase the ability of treated plants to resist P. cinnamomi attack. This action does not kill the fungus.
P. Cinnamomi infection on Schouten Island
The real distribution of P. cinnamomi will never be known. The resources required to map the distribution of the fungus, limit such actions to priority areas. Due to ongoing spread, these maps soon become out of date and unreliable. The current knowledge of the distribution of P. cinnamomi in Tasmania may be accessed through the Natural Values Atlas.
As a consequence of this management environment, the approach taken has been to focus on protecting plant species and communities that are most at risk, where goals are considered to be practicable and achievable in the long term. It is accepted that the disease epidemic will inevitably run its course in many areas through wildlife and water mediated spread. Preventing infestation of disease free areas is the primary goal for managing biodiversity assets. The assets identified for management are:
- threatened species that are susceptible to disease
- large disease-free areas of susceptible native vegetation
- highly susceptible communities
The report Conservation of Tasmanian Plant Species & Communities Threatened by Phytophthora cinnamomi identifies all the priority areas for management of the biodiversity assets at risk in Tasmania. These sites capture the large disease-free areas and biographically representative sites for the highly susceptible communities and at least three populations where possible for each P. cinnamomisusceptible threatened species.
Prescriptions that apply to prevent the introduction of Phytophthora root rot to uninfested areas include:
- managing developments and works that increase the risk of introduction eg roads and walking tracks;
- track rerouting, track hardening and drainage management, one way tracks and access management
- sourcing materials to be used in management works from P. cinnamomi-free stock
- sequencing and timing operations to reduce risk of introduction
- hygiene prescriptions such as washdown requirements
A bushwalker using creek crossing washdown station in a remote area
The Parks and Wildlife Service is encouraging visitors to follow basic washdown precautions before entering bushland areas. The Parks and Wildlife Service has providing boot washdown stations for public use on some walking tracks that enter Phytophthora root rot susceptible vegetation. These include disinfectant spray units at a number of trail heads and simpler scrubbing brush installations in remote areas that are carefully sited, so that the contaminated water from the washdown will flow back into the infested area.