Phytophthora.

The soil-borne pathogen, Phytophthora cinnamomi or cinnamon fungus, poses a significant threat to native forests.

It was first discovered in 1922 in Sumatra and is now one of the most widely distributed of all phytophthora species.

This pathogen spreads easily, causing disease, death and potential extinction in susceptible plants, and loss of habitat for animals.

It invades susceptible plant roots and can prevents them from taking up water and nutrients, resulting in root rot.

Phytophthora dieback is often difficult to detect but can cause permanent damage if it not is identified. It can remain dormant for long periods during dry weather and is impossible in most situations to eradicate.

Grass trees are particularly vulnerable and are often used as an indicator

It is generally accepted that P. cinnamomi is a newly introduced pathogen, probably arriving during European colonisation and then spread rapidly agricultural, soil movement and roads.

Particular attention was focused on the jarrah forests of Western Australia in the late 1960s, and the research was valuable for the rest of Australia.

It is mostly found mixed eucalypt forests along the coastal regions of Victoria, especially east Gippsland and around Anglesea. Infections in the heathlands of the Grampians were also notable.

Soil moisture and temperature were highly correlated with the spread and activity of the fungus and tree deaths. Poorly drained coastal soils were particularly susceptible. Older trees have a greater sensitivity to the disease than younger ones.

FCV studies in East Gippsland found that dieback epidemics occurred during years where a 3 or 4-month period of high rainfall occurred during the warmer months and was immediately followed by a similar period of low rainfall.

While fungicides can be effective, restricting soil movement, washing machinery and vehicles in combination with other hygiene measures are the most practical treatments in forested areas.

Marks GC and Idczak RM (1977) Phytophthora cinnamomi root rot investigations in Victoria” : A review with special reference to forestry.
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