Changes in the Distribution of Phytophthora cinnamomi in the Brisbane Ranges National Park Between 1970 and 1980-81

Abstract

The distribution of Phytophthora cinnamomi in the Brisbane Ranges National Park of Victoria was mapped and related to vegetation susceptibility, disease severity and past distribution. P. cinnamomi extended its distribution from 1% of the park in 1970 to 31% in 1980-81. The dispersal of the pathogen has occurred through roadworks and subsequent drainage of water-borne zoospores. In 1980-81, 50% of 1191 grids (250 x 250 m) occurred in susceptible vegetation (sclerophyllous forest/woodland). Of these, 45% (266 grids) were moderately diseased and 16% (95) severely diseased. Stands of dead trees occurred in 29 severely diseased grids which were in shallow gullies with impeded drainage. The 39% (231) of susceptible vegetation which remained unaffected occurred mainly on ridges and hilltops. P. cinnamomi was isolated from 3% of apparently resistant vegetation (graminoid forest/woodland). Restriction of access is recommended to the remaining areas of susceptible unaffected vegetation.

The impact of Phytophthora disease on riparian populations of common alder (Alnus glutinosa) in southern Britain

“…One of the most striking results obtained from the survey is that showing that the disease is many times more common in trees growing within 1 m of the river bank than in trees growing further away. This provides strong circumstantial evidence that propagules of the fungus are carried to new hosts via the water: a matter of considerable interest in that while it is well known that Phytophthora diseases can result from the dissemination of the pathogen via irrigation water or through the movement of rainwater through soil (SHEA et al 1983;DAWSON and WESTE 1985;EL-HAMALAWI and MENGE 1994;PRUNET and HERMAN 1995), there have been few instances involving a permanent watercourse. Apart from the situation described here, the only other example appears to be the lethal disease of Port Oxford cedar Chamaecyparis lawsoniana (Murr.)…”

Impacts of roads and linear clearings on tropical forests

“…Linear clearings are facilitating widespread species invasions in the tropics, for taxa ranging from little fire ants (Wasmannia auropunctuta), exotic earthworms and nonrainforest vertebrates, to fungal die-back, caused by Phytophthora spp., and myriad weed species [32,52,53,[57][58][59][60] (P. Byrnes, Honours thesis, James Cook University 2002). Some of these invaders are having major impacts on tropical biota.…”

Rate of Ocotea bullata Decline in Association with Phytophtora cinnamomi at Three Study Sites in the Southern Cape Indigenous Forests

“…cinnamomi has many of the characteristics of a secondary pathogen, in that in most cases it appears to attack trees which are already potentially under stress through waterlogging or drought (Wardlaw and Palzer, 1988;Dawson and Weste, 1985). Linking the occurrence of P. cinnamomi with waterlogging, Davison and Tay (1987) suggest that inoculation with P. cinnamomi may occur before and independently from waterlogging, but that such inoculation has little effect in well-drained soils.…”

“…Stinkwood trees can also survive fire because of their relatively thick, insulative bark and ability to coppice (Lubbe, 1990 b), but are sensitive to waterlogging, preferring well-drained soils (Geldenhuys et al, 1988;Ltibbe and Geldenhuys, 1990). The conservation status of stinkwood is affected by dieback associated with Phytophtora cinnamomi Rands (Von Broembsen, et al, 1986), a fungal pathogen of a wide variety of host plants worldwide (Podger, 1972;Brown and Qualischefski, 1983;Dawson and Weste, 1985;Hodges et al, 1986). P. cinnamomi has been recovered from a wide variety of indigenous and exotic plant species throughout South Africa (Von Broembsen, 1984).…”