DIEBACK (PHTOPHTHORA) SURVEYS

Phytophthora Dieback (Dieback) is the term used to describe the deadly introduced plant disease caused by Phytophthora cinnamomi (Pc) . There are over 50 species of Phytophthora, but the species that causes the most severe and widespread damage to native plants in Western Australia is P. cinnamomi.

The pathogen is believed to have been introduced to WA soon after European settlement in 1827. The first record of trees dying back was made in 1921. In the mid 1900’s, gravel underneath dying patches of forest was used to build roads, therefore inadvertently spreading P. cinnamomi throughout the south-west.

There are approximately 2300 susceptible species with thousands more acting as hosts. Indigenous species most affected belong to four families:

Proteaceae
Ericaceae
Fabaceae
Myrtaceae
The pathogen is restricted to the southwest land division and parts of the midwest that receive >400mm of annual rainfall. Distribution is correlated to rainfall where:

400-600mm – water gaining sites, severe disease may occur

600-800mm+ – widespread and extensive distribution over 20% of natural vegetation.

There are four main ways in which the pathogen is spread, these include:

Humans move infested material
Animals move infested material
Mycelium root to root growth
Autonomous mobility of zoospores
Why worry about Phytophthora Dieback?

Dieback creates environmental management problems for land use planning and development, road construction, timber harvesting, mining and other industries, since they involve movement of soil.

According to the most recent State of the Environment Report (Environmental Protection Authority 2007) Phytophthora Dieback, which is listed as a Priority 1 threat, is the third biggest threat to biodiversity after salinity and climate change. It is a more serious threat than weeds, clearing of native vegetation, acid sulphate soils and soil erosion.

Over 40% (2,300) of the native plant species and half of the endangered plant species in the south-west of WA are susceptible to the pathogen
Change in plant community composition and structure causes impacts throughout the whole ecosystem, including impacts on the local fauna
Dieback can lead to significant soil erosion as a result of the loss of susceptible vegetation.
Phytophthora Dieback Occurrence Mapping and Management Planning

Dinglebird Environmental provides specialist Dieback occurrence mapping and management planning services which include:

Interpretation of the target areas for the presence of Dieback
Mapping the area using the Department of Environment and Conservation (DEC) disease management categories i.e. Infested, Uninfested, Uninterpretable as well as determining if the area(s) in question are Protectable or Unprotectable.
Produce a disease occurrence map of the target areas showing DEC disease management categories and sample locations
Produce a report detailing the findings of the assessment
Development of Dieback management plans
Disease boundary rechecks
Rate of spread monitoring
Liaison with regulatory authorities