Ability of phosphite applied in a glasshouse trial to control Phytophthora cinnamomi in five plant species native to Western Australia

2001 ◽  
Vol 30 (4) ◽  
pp. 343 ◽  
Author(s):  
C. J. Wilkinson ◽  
J. M. Holmes ◽  
K. M. Tynan ◽  
I. J. Colquhoun ◽  
J. A. McComb ◽  
...  
1996 ◽  
Vol 44 (4) ◽  
pp. 433 ◽  
Author(s):  
BL Shearer ◽  
M Dillon

Estimates of the susceptibility of plant species in Banksia woodland to Phytophthora cinnamomi Rands were obtained by determining the incidence of plant death and frequency of isolation of the pathogen, among species occurring in 46 disease centres on the Swan Coastal Plain south of Perth, Western Australia. In the disease centres, dicotyledons outnumbered monocotyledons. About half of all species occurring in the disease centres were from four families of dicotyledons, with the largest number of species from the Myrtaceae, Proteaceae and Papilionaceae. The greatest number of species of monocotyledons were from the Anthericaceae and Cyperaceae. No deaths were recorded for 47% of species found in three or more disease centres. These species were mainly from the Cyperaceae, Haemodoraceae, Myrtaceae and Papilionaceae. The species that tended to die frequently in disease centres were mainly from the Papilionaceae, Proteaceae, Epacridaceae, Xanthorrhoeaceae and the Zamiaceae. Phytophthora cinnamomi was isolated from 26 of the 95 species occurring in three or more disease centres. For most species, the frequency of isolation of P. cinnamomi from recently dead plants was much less than the frequency of dead plants sampled. Isolation from plants was less frequent than from adjacent soil. The pathogen was isolated from recently dead plants or soil mainly for species of the Proteaceae, Myrtaceae, Papilionaceae, Dasypogonaceae, Iridaceae and Xanthorrhoeaceae. Cross-tabulation of species by incidence of plant death and isolation of P. cinnamomi from plant and soil, provided the opportunity to classify the response of plant species to infection by P. cinnamomi.


2007 ◽  
Vol 55 (3) ◽  
pp. 225 ◽  
Author(s):  
B. L. Shearer ◽  
C. E. Crane ◽  
S. Barrett ◽  
A. Cochrane

The invasive soilborne plant pathogen Phytophthora cinnamomi Rands is a major threatening process in the South-west Botanical Province of Western Australia, an internationally recognised biodiversity hotspot. Comparatively recent introduction of P. cinnamomi into native plant communities of the South-west Botanical Province of Western Australia since the early 1900s has caused great irreversible damage and altered successional change to a wide range of unique, diverse and mainly susceptible plant communities. The cost of P. cinnamomi infestation to community values is illustrated by examination of direct (mortality curves, changes in vegetation cover) and indirect impacts on biodiversity and ecosystem dynamics, the proportion of Threatened Ecological Communities infested, Declared Rare Flora either directly or indirectly threatened by infestation and estimates of the proportion of the native flora of the South-west Botanical Province susceptible to the pathogen. While direct impacts of P. cinnamomi have been poorly documented in the South-west Botanical Province, even less attention has been given to indirect impact where destruction of the habitat by the pathogen affects taxa not directly affected by infection. Current poor understanding and quantification of indirect impacts of P. cinnamomi through habitat destruction results in an underestimation of the true impact of the pathogen on the flora of the South-west Botanical Province. Considerable variation of susceptibility to P. cinnamomi among and within families of threatened flora and responses of taxa within the genus Lambertia show how classification within family and genus are poor predictors of species susceptibility. Within apparently susceptible plant species, individuals are resistant to P. cinnamomi infection. Intra-specific variation in susceptibility can be utilised in the long-term management of threatened flora populations and needs to be a high research priority. Current control strategies for conservation of flora threatened by P. cinnamomi integrate hygiene and ex situ conservation with disease control using fungicide. Application of the fungicide phosphite has proven effective in slowing progress of P. cinnamomi in infested, threatened communities. However, variation in plant species responses to phosphite application is a major factor influencing effective control of P. cinnamomi in native communities. A greater understanding of the mechanisms of action of phosphite in plant species showing different responses to the fungicide may provide options for prescription modification to increase phosphite effectiveness in a range of plant species. The range of responses to P. cinnamomi infection and phosphite application described for Lambertia taxa suggests that the genus would make an ideal model system to elucidate the mechanisms of resistance to P. cinnamomi and the effectiveness of phosphite against the pathogen.


2007 ◽  
Vol 29 (1) ◽  
pp. 25 ◽  
Author(s):  
S.D. Bradshaw ◽  
R.D. Phillips ◽  
S. Tomlinson ◽  
R. J. Holley ◽  
S. Jennings ◽  
...  

The Honey possum, Tarsipes rostratus, is an obligate nectarivore, known to feed on plant species from only three Families in south-western Western Australia: Myrtaceae, Proteaceae and Epacridaceae. These plants can be adversely affected by fire, decreased rainfall or groundwater levels and the pathogen Phytophthora cinnamomi. We investigated the ecology of T. rostratus in terms of: (i) how the population fluctuated in response to rainfall and fire over a 20-year period and (ii) changes in diet and movements during a period of decreased food availability in late summer. Mean capture rates were significantly positively correlated with mean flowering rates of Banksia ilicifolia over a 20-year period. Winter capture rates were also significantly positively correlated with both annual and winter rainfall two years prior to trapping in recently burnt areas, but not in long unburnt� areas. Capture rates were significantly higher in unburnt Banksia woodland during winter but densities there have declined since 1996, associated with the death of many Banksia ilicifolia trees from persistent Phytophthora infection. Notwithstanding this decline, winter capture rates in the unburnt areas were still approximately double those in the burnt areas 6 years after the last fire. Short-term capture rates were negatively correlated with barometric pressure, showing that movement and foraging is stimulated by the passage of low pressure frontal weather systems. Despite the paucity of known food sources flowering in late summer and autumn, there was no evidence of T. rostratus using plant species from other than the three above-noted Families. Utilisation areas in summer were also no larger than those previously recorded across all seasons in Scott National Park. Some individuals, however, moved extensive distances to locate spatially restricted food sources. The conservatism of their diet and the sensitivity of the population to changes in rainfall and fire history indicate that T. rostratus populations are particularly vulnerable to some of the environmental changes now occurring in south-western Australia.


2014 ◽  
Vol 62 (7) ◽  
pp. 587 ◽  
Author(s):  
Nicole Moore ◽  
Sarah Barrett ◽  
Kay Howard ◽  
Michael D. Craig ◽  
Barbara Bowen ◽  
...  

Fires are features of ecological communities in much of Australia; however, very little is still known about the potential impact of fire on plant diseases in the natural environment. Phytophthora cinnamomi is an introduced soil-borne plant pathogen with a wide host range, affecting a large proportion of native plant species in Australia and other regions of the world, but its interaction with fire is poorly understood. An investigation of the effects of fire on P. cinnamomi activity was undertaken in the Stirling Range National Park of south-western Australia, where fire is used as a management tool to reduce the negative impact of wildfires and more than 60% of the park is infested with, and 48% of woody plant species are known to be susceptible to, P. cinnamomi. At eight sites confirmed to be infested with P. cinnamomi, the proportion of dead and dying susceptible species was used as a proxy for P. cinnamomi activity. Subset modelling was used to determine the interactive effects of latest fire interval, average fire interval, soil water-holding capacity and pH on P. cinnamomi activity. It was found that the latest and average fire interval were the variables that best explained the variation in the percentage of dead and dying susceptible species among sites, indicating that fire in P. cinnamomi-infested communities has the potential to increase both the severity and extent of disease in native plant communities.


2001 ◽  
Vol 49 (6) ◽  
pp. 761 ◽  
Author(s):  
K. M. Tynan ◽  
C. J. Wilkinson ◽  
J. M. Holmes ◽  
B. Dell ◽  
I. J. Colquhoun ◽  
...  

This study examined the ability of foliar applications of the fungicide phosphite to contain colonisation of Phytophthora cinnamomi in a range of plant species growing in natural plant communities in the northern sandplain and jarrah (Eucalyptus marginata) forest of south-western Australia. Wound inoculation of plant stems with P. cinnamomi was used to determine the efficacy of phosphite over time after application. Colonisation by P. cinnamomi was reduced for 5–24 months after phosphite was applied, depending on the concentration of phosphite used, plant species treated and the time of phosphite application. Plant species within and between plant communities varied considerably in their ability to take up and retain phosphite in inoculated stems and in the in planta concentrations of phosphite required to contain P. cinnamomi. As spray application rates of phosphite increased from 5 to 20 g L–1, stem tissue concentrations increased, as did the ability of a plant species to contain P. cinnamomi. However, at application rates of phosphite above 5 g L–1 phytotoxicity symptoms were obvious in most species, with some plants being killed. So, despite 10 and 20 g L–1 of phosphite being more effective and persistent in controlling P. cinnamomi, these rates are not recommended for application to the plant species studied. The results of this study indicate that foliar application of phosphite has considerable potential in reducing the impact of P. cinnamomi in native plant communities in the short-term. However, in order to maintain adequate control, phosphite should be sprayed every 6–12 months, depending on the species and/or plant community.


1982 ◽  
Vol 30 (2) ◽  
pp. 139 ◽  
Author(s):  
WM Blowes ◽  
WA Heather ◽  
N Malajczuk ◽  
SR Shea

Native forest at Durras in south-eastern New South Wales and Jarrahdale in south-western Western Australia was examined for the presence of Phytophthora cinnamomi by two sampling and isolation techniques. With the lupin seeding baiting technique, randomly selected samples of soil and fine roots collected from the New South Wales site yielded P. cinnamomi when baited, while similar baiting of comparable samples from Western Australia failed. Direct plating of samples of upper roots and root collars of recently dead Banksia grandis from Western Australian sites yielded P. cinnamomi, while this organism was not isolated from comparable samples of chlorotic Macrozamia communis collected at the New South Wales site. The results suggest that the form of occurrence of P. cinnamomi and its association with disease in Australia vary in different situations. Viewing each situation independently might ensure the adoption of control/prevention strategies appropriate to all.


Plant Disease ◽  
2009 ◽  
Vol 93 (3) ◽  
pp. 215-223 ◽  
Author(s):  
Treena I. Burgess ◽  
Janet L. Webster ◽  
Juanita A. Ciampini ◽  
Diane White ◽  
Giles E. StJ. Hardy ◽  
...  

For 30 years, large-scale aerial photography has been used to map the extent of Phytophthora dieback disease in native forests in the southwest of Western Australia, with validation of the observations involving routine testing of soil and root samples for the presence of Phytophthora cinnamomi. In addition to P. cinnamomi, six morpho-species have been identified using this technique: P. citricola, P. megasperma, P. cryptogea, P. drechsleri, P. nicotianae, and P. boehmeriae. In recent years, many new Phytophthora species have been described worldwide, often with similar morphology to existing species; thus, as many of the isolates collected in Western Australia have been difficult to identify based on morphology, molecular identification of the morpho-species is required. Based on amplification of the internal transcribed spacer (ITS) region of the rDNA gene, sequence data of more than 230 isolates were compared with those of existing species and undescribed taxa. P. inundata, P. asparagi, P. taxon PgChlamydo, P. taxon personii, and P. taxon niederhauserii were identified based on sequence data. Phylogenetic analysis revealed that nine potentially new and undescribed taxa can be distinguished. Several of the new taxa are morphologically indistinguishable from species such as P. citricola, P. drechsleri, and P. megasperma. In some cases, the new taxa are closely related to species with similar morphology (e.g., P.sp.4 and P. citricola). However, the DNA sequences of other new taxa such as P.sp.3 and P.sp.9 show that they are not closely related to morphologically similar species P. drechsleri and P. megasperma, respectively. Most of the new taxa have been associated with dying Banksia spp., while P.sp.2 and P.sp.4 have also been isolated from dying Eucalyptus marginata (jarrah). Some taxa (P.sp.3, 6, and 7) appear to have limited distribution, while others like P.sp.4 are widespread.


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