Phytophthora Dieback The biological bulldozer Adapted from presentations
Phytophthora Dieback The biological bulldozer Adapted from presentations by Dr Chris Dunne, Science Division, DEC
Threats to rare flora of the south-west of WA Consequences of construction developments i. e. road works, recreation Small/declining populations Demographic /genetic effects Phytophthora dieback Invasive weeds Grazing by feral/ introduced animals Salinity, water table change Mining activities Drought/climate change Land clearing
What is Phytophthora dieback? n Caused by a water mould called Phytophthora cinnamomi n n Phytophthora is Greek for ‘plant destroyer’ organism was first identified on the roots of a cinnamon tree P. cinnamomi feeds off plant roots Causes root rot which stops plant taking up nutrients and water
A brief history Quarantine Infested gravel used for roadmaking 1829 Introduction of European plant species 1920 1948 1989 1964 1973 1996 Research station est. Dwellingup Pc identified as causal agent Early European settlers arrive First recorded unexplained tree deaths (Karragullen) Use of phosphite
Lifecycle of P. cinnamomi
Ideal environment >800 mm 20 o. C-30 o. C p. H 5 -6 n Therefore: n n Forested areas with higher rainfall Grows and spreads best in autumn and spring
Where is dieback found? bushland gardens nurseries horticultural plantations
Impact on native flora n Of 5710 recorded species of plant: n n 2300 (40%) susceptible to Phytophthora dieback 800 (14%) highly susceptible to Phytophthora dieback
Jarrah forest – Dwellingup
Banksia woodland
Stirling Range National Park
South Coast
Impact on animals? n Loss of: n n n food habitat shelter
Distribution of Phytophthora cinnamomi
P. cinnamomi in Western Australia
Perth Scarp
How is it spread? 4 WD Hiking boots Road making Animals Irrigation Trail/mountain bikes Infected plant material
Management of Phytophthora dieback n Interpretation and mapping n n Identify priority areas, species or communities for protection n n n Is Phytophthora dieback known or likely to be in an area, or at your site? Do you need more information? Declared rare flora Endangered fauna Is the area protectable Prevent accidental introduction Minimise spread Reduce impact
Dieback Interpretation & Mapping n Dead “indicator plants” n n n Structural change Chronology of deaths Soil/tissue sampling
Indicator species Banksia grandis (Bull Banksia) Patersonia spp. (Flag Flower) Xanthorrhoea preissii (Balga)
Field Detection Direction of travel Disease Front Depauperate sedgeland Rich proteaceous shrubland
Identify protectable areas n Focus resources on areas of highest biodiversity value n n Focus resources on areas which can be protected n n Declared rare fauna Endangered fauna Threatened ecological communities Uphill from known infections Large enough to protect (>2 ha) Able to be effectively quarantined (limited public access, sources of infection can be mitigated or removed) Focus resources on areas where the benefits of hygiene will last more than a few decades
Prevent accidental introduction n Readily introduced in infested material (e. g. soil on footwear or vehicles, infected plant material, gravel for road construction, nursery stock) Impossible to eradicate n Prevent introduction by n n Use of certified dieback free materials Remove and control access Hygiene – footbaths and vehicle washdown
Remove and control access X X X CLEAN ON ENTRY POINT X
Remove access Control access
Hygiene Footwear & equipment Vehicles
Minimise spread Reduce water flow Barriers to infection
Reduce impact - conservation Seedbank Translocation Revegetation
Phosphite n n Highly effective – gives short term resistance to some plants Low toxicity Environmentally friendly Can be sprayed or injected
What can you do?
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