A list of Australian plant responses to Phytophthora cinnamomi has been compiled1 (Table A4.1) from published material and the unpublished records and observations of individual researchers. Comments, corrections and suggested additions should be sent to firstname.lastname@example.org
‘Are there species present for which the impact of P. cinnamomi would be significant?’
The critera for the level of threat to vegetation at a site, that warrants management of P. cinnamomi, is currently impossible to prescribe for nationally. The different States will need to exercise discretion on the criteria, and criteria need to be developed as a first step in planning the management of P. cinnamomi.
Table A4.1 contains species that range from highly susceptible to field resistant. In response to the question posed in the decision flowchart (Figure 5.1) ‘Are there species present for which the impact of P. cinnamomi would be significant’, it is suggested that the answer is ‘yes’ if:
there are species present that are listed in the table as moderately (MS) or highly susceptible (HS)
there are species and ecological communities present that are threatened and the extent of susceptibility to P. cinnamomi is unknown.
Threatened species and ecological communities
The Australian Government Environmental Protection & Biodiversity Conservation Act 1999 (EPBC Act)is national legislation that promotes the conservation of Australia’s biodiversity. Nationally threatened taxa, listed in schedules of the EPBC Act, are denoted in Table A4.1. General and spatial information on nationally listed taxa is available from the Protected Matters Search Tool on the Australian Government DEH website.
Each Australian State and Territory has its own environmental legislation for listing threatened taxa based on State/Territory boundaries. The status of species in individual States and Territories does not appear in Table A4.1; therefore the determination of the potential impact of P. cinnamomi at a site should also include consultation of the relevant State/Territory lists. Links to each of the State and Territory sites relating to listing of threatened taxa are provided below:
Australian Capital Territory
New South Wales
Profiles of flora and fauna of NSW are available in a Wildlife Atlas
Table A4.1 is not solely a host list. Whilst it does contain the known Australian native hosts of P. cinnamomi, the fact that a species can be a host does not mean that it will display symptoms of infection in the wild. The responses of native plants to infection by P. cinnamomi are many and various:
hosts of P. cinnamomi in the wild may show no obvious symptoms of infection
the response of a species in the wild may depend on static site conditions (e.g. substrate and pH) and temporal conditions (e.g. rainfall and disturbances such as fire)
species may be affected in some situations (e.g. in cultivation or glasshouse experiments) but largely unaffected in others (e.g. in the wild)
there may be spatial variation in the response (e.g. Hibbertia hypericoides is highly susceptible to infection on the Swan Coastal Plain of WA but rarely affected in the adjoining jarrah forest)
species may not be hosts of P. cinnamomi at all, but may be affected nonetheless by changes in habitat caused by the death of surrounding plants.
An effort has been made in Table A4.1 to indicate the field susceptibility of species to infection and spatial variation in susceptibility where they are known. The list is indicative and not definitive. We suggest that it is used as an indication of the potential impact of P. cinnamomi on native plants and vegetation, and should not replace careful site evaluation (e.g. sampling of roots and soil for the presence of the pathogen and long-term monitoring). As the information in Table A4.1 will require some interpretation it is strongly recommended that the following points are noted prior to consulting or using the information:
the listing of a taxon in Table A4.1 as a host or as a susceptible species in one State or Territory does not necessarily mean that it is a host or is susceptible to infection across its range
no attempt has been made in the list to evaluate the veracity of susceptibility ratings. Please read the cited reference to make this assessment yourself
references provided in the list should be sought to clarify issues of variable susceptibility. In addition, the list is a work in progress - many more species will be added in the future, and many of the susceptibility ratings will be altered as we gain a better understanding of the effects of the pathogen over a greater time and over the entire area that it is capable of reaching
Explanatory Notes on Table A4.1
In the list the name given to a taxon is that currently shown as accepted in the Australian Plant Name Index. Taxa that have been split since the referenced work was published or for which no indication was given in a reference of the subspecific rank, are indicated by s.l. (sensu lato, in the broadest sense). Nationally threatened taxa, listed in schedules of the EPBC Act, are denoted in the table as CE (critically endangered), E (endangered) or V (vulnerable).
The distribution of taxa is indicated by the State or Territory in which they have been recorded: n = New South Wales and the Australian Capital Territory, nt = Northern Territory, q = Queensland, s = South Australia, t = Tasmania, v = Victoria, w = Western Australia; saf = South Africa (plantation species).
The numbers in the body of the Table refer to the numbered references in the References section.
Species from which P. cinnamomi has been isolated have been separated into; those growing in the wild, those grown in cultivation (mostly botanic gardens), and those used in experiments to test for susceptibility. Experimental isolations were generally performed in a glasshouse environment. A few, indicated by a *, were obtained by inoculating propagated plants in the field.
The susceptibility of a taxon, where known, is indicated by a rating adapted from previously used systems:
HS – highly susceptible, i.e. species that are frequently and consistently killed in the wild following infection by P. cinnamomi, and/or appear to decline or be rare on infested sites (includes scale categories 10, 11, and 12 of Wills40 and Barrett59, and groups 3 and 5 of Shearer and Dillon14)
MS – moderately susceptible (or variable susceptibility), i.e. species that are often killed following infection by P. cinnamomi in the wild but many plants of which commonly survive (includes scale categories 7, 8 and 9 of Wills40 and Barrett59, and group 4 of Shearer and Dillon14)
LS – low susceptibility, i.e. species that are rarely but occasionally found dead on infested sites (includes scale categories 4, 5 and 6 of Wills40 and Barrett59, and group 2 of Shearer and Dillon14)
S – susceptible and thought to be affected, but degree of susceptibility not documented
SP - susceptible but persistent, i.e. species that are frequently killed following infection by P. cinnamomi in the wild but which persist on affected sites through effective reproductive strategies
SV – variable susceptibility; plants may be commonly killed on some infested sites but appear unaffected on others – this may be attributable to genetic differences between populations or differences in site characteristics that influence plant responses
FR - field resistant (or tolerant), i.e. species that appear to be unaffected by P. cinnamomi in the wild when it is present and for which deaths in the field can rarely be associated with infection by P. cinnamomi (includes scale categories 1, 2 and 3 of Wills40 and Barrett59, and group 1 of Shearer and Dillon14)
Q – not known to be directly affected by P. cinnamomi but rarely found on affected sites (and may be affected either directly through infection or through changes in habitat).
Table A4.1 A list of Australian native plants that are potential hosts of Phytophthora cinnamomi. Please consult the accompanying text before using this list.