Pathogenicity of Phytophthora multivora to Eucalyptus gomphocephala and Eucalyptus marginata

Phytophthora multivora is associated with the rhizosphere of declining Eucalyptus gomphocephala, Eucalyptus marginata and Agonis flexuosa. Two pathogenicity experiments were conducted. The first experiment examined the pathogenicity of five P. multivora isolates and one Phytophthora cinnamomi isolate on the root systems of E. gomphocephala and one P. multivora isolate on the root system of E. marginata. In the second experiment, the pathogenicity of P. multivora to E. gomphocephala and E. marginata saplings was measured using under-bark stem inoculation. In Experiment 1, the P. cinnamomi isolate was more aggressive than all P. multivora isolates causing significant loss of fine roots and plant death. Two P. multivora isolates and the P. cinnamomi isolate caused significant losses of E. gomphocephala fine roots 0–2 mm in diameter and significantly reduced the surface area of roots 0–1 mm in diameter. One P. multivora and the P. cinnamomi isolate significantly reduced the surface area of roots 1–2 mm in diameter. Two of the P. multivora isolates significantly reduced the number of E. gomphocephala root tips. In E. marginata, the length and surface area of roots 0–1 mm in diameter and number of root tips were significantly reduced by P. multivora infestation. Rhizosphere infestation with the P. multivora isolates and P. cinnamomi isolate on E. gomphocephala, and one P. multivora isolate on E. marginata, did not significantly influence the foliar nutrient concentrations. In Experiment 2, under-bark inoculation with P. multivora caused significant lesion extension in E. gomphocephala and E. marginata saplings, compared to the control. We propose that P. multivora is inciting E. gomphocephala and E. marginata decline by causing fine root loss and subsequently interfering with nutrient cycling throughout the plant. The impact of fine root loss on the physiology of plants in sites infested with P. multivora requires further research.

[1]  J. Kinal,et al.  Temporal and spatial soil inoculum dynamics following Phytophthora cinnamomi invasion of Banksia woodland and Eucalyptus marginata forest biomes of south-western Australia , 2010, Australasian Plant Pathology.

[2]  B. Dell,et al.  Soil bacterial functional diversity is associated with the decline of Eucalyptus gomphocephala , 2010 .

[3]  A. Montaghi,et al.  Distribution and gradient analysis of Ink disease in chestnut forests , 2010 .

[4]  T. Jung,et al.  Beech decline in Central Europe driven by the interaction between Phytophthora infections and climatic extremes , 2009 .

[5]  T. Burgess,et al.  Botryosphaeriaceae from tuart (Eucalyptus gomphocephala) woodland, including descriptions of four new species. , 2009, Mycological research.

[6]  T. Burgess,et al.  Re-evaluation of Phytophthora Species Isolated During 30 Years of Vegetation Health Surveys in Western Australia Using Molecular Techniques. , 2009, Plant disease.

[7]  T. Burgess,et al.  Phytophthora multivora sp. nov., a new species recovered from declining Eucalyptus, Banksia, Agonis and other plant species in Western Australia , 2009, Persoonia.

[8]  W R.,et al.  Comparisons of Treatments After an Analysis of Variance in Ecology , 2007 .

[9]  U. Jönsson,et al.  A conceptual model for the development of Phytophthora disease in Quercus robur. , 2006, The New phytologist.

[10]  Neville Nicholls,et al.  Shifts in the synoptic systems influencing southwest Western Australia , 2006 .

[11]  R. Archibald.  Fire and the persistence of tuart woodlands , 2006 .

[12]  T. Jung,et al.  Relationships between health of Quercus robur, occurrence of Phytophthora species and site conditions in southern Sweden , 2005 .

[13]  B. Dell,et al.  History of Phytophthora cinnamomi management in Western Australia , 2005 .

[14]  U. Jönsson.  Phytophthora species and oak decline - can a weak competitor cause significant root damage in a nonsterilized acidic forest soil? , 2004 .

[15]  T. Edwards.  Environmental correlates and associations of tuart (Eucalyptus gomphocephala) decline , 2004 .

[16]  A. Vannini,et al.  Evaluation of root damage to English walnut caused by five Phytophthora species , 2003 .

[17]  T. Jung,et al.  Pathogenicity of Swedish isolates of Phytophthora quercina to Quercus robur in two different soils , 2003 .

[18]  C. Yates,et al.  The Biology of Tuart , 2002 .

[19]  T. Jung,et al.  Involvement of soilborne Phytophthora species in Central European oak decline and the effect of site factors on the disease , 2000 .

[20]  T. Jung,et al.  Phytophthora quercina sp. nov., causing root rot of European oaks , 1999 .

[21]  E. Hansen,et al.  Phytophthora species in oak forests of north-east France , 1999 .

[22]  T. Jung,et al.  Isolation, identification and pathogenicity of Phytophthora species from declining oak stands , 1996 .

[23]  G. Hardy,et al.  The ability of Phytophthora cinnamomi to infect through unwounded and wounded periderm tissue of Eucalyptus marginata , 1996 .

[24]  B. Shearer,et al.  Impact and Disease Centre Characteristics of Phytophthora cinnamomi Infestations of Banksia Woodlands on the Swan Coastal Plain, Western Australia , 1996 .

[25]  F. Bunny.  The biology, ecology and taxonomy of Phytophthora citricola in native plant communities in Western Australia , 1996 .

[26]  C. Brasier,et al.  Phytophthora cinnamomi and oak decline in southern Europe. Environmental constraints including climate change , 1996 .

[27]  C. Bennington,et al.  Use and Misuse of Mixed Model Analysis of Variance in Ecological Studies , 1994 .

[28]  J. Scott,et al.  European oak declines and global warming: a theoretical assessment with special reference to the activity of Phytophthora cinnamomi , 1994 .

[29]  C. Brasier,et al.  Evidence for Phytophthora cinnamomi involvement in Iberian oak decline , 1993 .

[30]  B. Shearer,et al.  Dispersal of Phytophthora cinnamomi through lateritic soil by laterally flowing subsurface water , 1993 .

[31]  Robert W. Day,et al.  Comparisons of Treatments After an Analysis of Variance in Ecology , 1989 .

[32]  B. Schaffer,et al.  Effects of flooding and Phytophthora root rot on net gas exchange and growth of avocado , 1989 .

[33]  P. Somerford,et al.  Effects of isolate and time of inoculation on invasion of secondary phloem of Eucalyptus spp. and Banksia grandis by Phytophthora spp. , 1988 .

[34]  B. Shearer,et al.  Variation in seasonal population fluctuations of Phytophthora cinnamomi within and between infected Eucalyptus marginata sites of southwestern Australia , 1987 .

[35]  B. Shearer,et al.  Comparative Behaviour of Phytophthora Species in the Secondary Phloem of Stems and Excised Roots of Banksia grandis and Eucalyptus marginata , 1987 .

[36]  Ds Crombie,et al.  Water relations of root-pruned jarrah (Eucalyptus marginata Donn ex Smith) saplings. , 1987 .

[37]  M. Matheron,et al.  Pathogenicity and relative virulence of Phytophthora spp. from walnut and other plants to rootstocks of English walnut trees , 1985 .

[38]  M. Stukely,et al.  Genetic variation in resistance of Pinus radiata to Phytophthora cinnamomi , 1984 .

[39]  P. L. Searle.  The berthelot or indophenol reaction and its use in the analytical chemistry of nitrogen. A review , 1984 .

[40]  B. Dell,et al.  Periodicity of fine root growth in Jarrah (Eucalyptus marginata Donn ex Sm.) , 1983 .

[41]  B. Shearer,et al.  Distribution, reproduction, and movement of Phytophthora cinnamomi on sites highly conducive to jarrah dieback in South Western Australia , 1983 .

[42]  W. Heather,et al.  The Distribution of Phytophthora cinnamomi Rands at Two Sites in Southern Western Australia and at Durras in South-Eastern New South Wales. , 1982 .

[43]  G. Weste,et al.  Changes in Water Relations Associated With Infection by Phytophthora cinnamomi , 1982 .

[44]  B. Dell,et al.  Structure of the Surface Root System of Eucalyptus Marginata Sm. And Its Infection by Phytophthora Cinnamomi Rands , 1981 .

[45]  G. Bartle,et al.  Landforms and soils as an aid to urban planning in the Perth metropolitan north west corridor, Western Australia , 1980 .

[46]  S. Shea,et al.  Seasonal variation in population levels of Phytophthora cinnamomi Rands in soil in diseased, freely-drained Eucalyptus marginata Sm sites in the northern Jarrah forest of South-Western Australia. , 1980 .

[47]  Shea,et al.  Variation in sporangial production of Phytophthora cinnamomi Rands on Jarrah (Eucalyptus marginata Sm.) forest sites with different understorey compositions. , 1978 .

[48]  F. Podger.  Phytophthora cinnamomi, a Cause of Lethal Disease in Indigenous Plant Communities in Western Australia , 1972 .

[49]  F. James Rohlf,et al.  Biometry: The Principles and Practice of Statistics in Biological Research , 1969 .

[50]  G. F. Gravatt,et al.  Root disease of Castanea species and some coniferous and broadleaf nursery stocks, caused by Phytophthora cinnamomi. , 1945 .