Phytophthora dieback is a serious environmental threat to natural values. Unlike many other threats, once established it can not be eradicated and recovery to the vegetations previous state will not occur. Once established in an area Phytophthora cinnamomi creates a permanent change to the ecosystem which is likely to slowly spread over time. Naturally the pathogen will spread through the movement of water, activities of animals and also slowly through its own growth and reproduction. There is practically nothing that can be done to control this natural spread in native plant communities.
Maintain good biosecurity practices
Unlike with natural spread humans have the capacity to transport the pathogen long distances and across barriers. Therefore, by far the most important management tool for Phytophthora dieback is to effectively manage the risk our activities create of spreading the pathogen within areas it already occurs, or more importantly into areas which are currently free of infections. Given that there is no way of knowing everywhere that P. cinnamomi is present, or not, maintaining good biosecurity actions is the best way to approach this. Biosecurity management actions include things like:
- 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
Preventing infestation of disease free areas is the primary goal for managing biodiversity assets. All susceptible vegetation that is currently free of Phytophthora dieback should be priorities, however some of the most significant assets to protect are:
The report Conservation of Tasmanian Plant Species & Communities Threatened by Phytophthora cinnamomi identifies the highest 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 susceptible threatened species.
On reserved lands visitors are encouraged to follow basic washdown precautions. In priority areas boot washdown stations are provided to facilitate this.
These include disinfectant spray units at trail heads.
Treatment of Phytophthora dieback to reduce impacts
Although Phytophthora cinnamomi cannot be eradicated
there is the potential to treat Phytophthora dieback to reduce impacts. The systemic
non-hazardous fungicide, phosphite, can be used in some environments to
suppress the natural spread of the pathogen and boost the natural defences of
the treated plants. Treatment with phosphite is an ongoing commitment as regular
reapplication is required, but it is a potentially valuable tool to protect high
priority species, communities and habitats.
Special permitting is required to legally use phosphite to treat native
vegetation, and in some communities the chemical itself can be toxic to some
plant species. work is currently
underway to better understand the potential uses for phosphite in Tasmania.