Colquhoun, I.J.

Hardy, G.E.St.J.

Hüberli, D.

Tommerup, I.C.

English

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Phytophthora in Australasia and the way forward in disease management G.E.St.J. HardIE, I.C TommerupB,  I.  CoLquhounC and B.L. Shearel' ASchool of  Biological Sciences and Biotechnology, Murdoch University, Murdoch, Western Australia, 6150 BDivision of  Forestry and Forestry Products, CSIRO, Wembley, Western Australia C Alcoa World Alumina, Environmental Department, Booragoon, 6953, Western Australia DDepartment of  Conservation and Land Management, Science Division, Kensington, 6983, Western Australia ECorresponding author; email: g-hardy@murdoch.edu.au Abstract. Unlike the USA and Europe, Australasia has not in  the last two years faced any unexpected developments in  new Phytophthora diseases in forests  and natural ecosystems. Consequently, we will focus  on the way forward  for  disease  management and examine the challenges that will  need to  be faced over the next few years to control the impact and rate of  spread of  this disease. Measuring resistance in jarrah, Eucalyptus marginata, to Phytophthora cinnamomi: What factors change disease expression? D. HuberliAD, I.C TommerupB, l. CoLquhounC and G.E. Sf.J. Hardy" 'School of Biological Sciences and Biotechnology, Murdoch University, Murdoch, W. Australia 6150 "Forestry and Forest Products, CSIRO Perth, PO Box 5, Wembley 6913, W. Australia cAlcoa World Alumina Australia, Environmental Department, PO Box 252, Applecross 6153, W. Australia DCorresponding author; email: dhuberli@nature.berkeley.edu Abstract.  The interaction between Eucalyptus marginata (jarrah), the dominant and important timber species in jarrah forests, and Phytophthora cinnamomi, is not a co-evolved one. Jarrah appears to have a wide range of  variability in resistance to P.  cinnamomi in the forest. Jarrah clonal lines resistant (RR) and susceptible (SS) to the pathogen have been produced (I). Our glasshouse mortality trial showed that the capacity of 73  isolates to cause disease ranged from killing all plants (59 days) to plants being symptomless (182 days) (2). Comparison of branch and root inoculations in situ confirmed that branches are a valid option for testing resistance ofyoungjarrah (3).  No jarrah clonal  line  maintained  its  resistance  level  in  a  series of experiments  using  different inoculation methods,  different environmental  conditions and when challenged by individuals  from  a large range of  P.  cinnamomi isolates (2-4). Even the most promising RR line had replicates that became diseased with time in various treatments. To develop robust resistance, further screening work may be required using more isolates varying in their capacity to cause disease and a broader range of environmental conditions that favour the pathogen, particularly at 25-30°C  (4).  Jarrah trees are affected by many environmental conditions during their life cycle (500-1000 years). Consequently, clonal lines that survive such rigorous screening may be durably resistant and survive in disease impacted sites. 1.  McComb  et  al.  (1990).  Selection  and  propagation  of jarrah  for  dieback  resistance- -A progress  report.  Combined Proceedings of  the International Plant Propagators' Society 40,86-90 2.  Hiiberli et al.  (200!). Phenotypic variation in a clonal lineage of  two Phytophthora cinnamomi populations from Western Australia. Mycological Research,. 105,1053-1064. 3.  Hiiberli ef al. Evaluation of resistance to Phytophthora cinnamomi in seed-grown trees and clonal lines of Eucalyptus marginata inoculated in lateral branches and roots. Plant Pathology. 51,435-442. 4.  Hiiberli et al.  (2002). Temperature and inoculation method influence disease phenotypes and mortality  of Eucalyptus  marginata  clonal  lines  inoculated  with  Phytophthora  cinnamomi. Australasian Plant Pathology. 31, 107-118. 259 

Measuring resistance in jarrah, Eucalyptus marginata, to Phytophthora cinnamomi: what factors change disease expression?

http://researchrepository.murdoch.edu.au/3082/

Measuring resistance in jarrah, Eucalyptus marginata, to Phytophthora cinnamomi: what factors change disease expression?

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