Infection of Mycosphaerella species on Eucalyptus species in Western Australia
Jackson, S.L., Maxwell, A., Neumeister-Kemp, H.G. and Hardy, G.E.St.J. (2003) Infection of Mycosphaerella species on Eucalyptus species in Western Australia. In: 8th International Congress of Plant Pathology: Solving problems in the real world, (ICPP 2003), 2 - 7 February, Christchurch; New Zealand.
The most serious foliar pathogen threatening the eucalypt estate in Western Australia (WA) is Mycosphaerella leaf blotch (MLB). In Western Australia, there is a growing concern that fungal pathogens of the exotic E. globulus could spread into native forest or vice versa. Recently Mycosphaerella cryptica has been isolated from two of the most important endemic eucalypt species, Eucalyptus diversicolor and E. marginata. Another MLB pathogen in WA is M. nubilosa, so far only recorded on E. globulus. The ability for the species occurring on E. globulus to infect and cause disease on endemic eucalypts is unknown. Increasing numbers of Mycosphaerella species are being described from endemic and plantation eucalypts in Western Australia, including M. lateralis, which has not so far been recorded elsewhere in Australia. No infection work has been conducted on M. lateralis, its anamorph, Dissoconium dekkeri, or M. marksii. Infection studies of .M cryptica and M. nubilosa on E. diversicolor, E.marginata, E. globulus and Corymbia calophylla were conducted. For the first time, M. nubilosa ascospores were shown to penetrate the leaf surface of E. diversicolor through stomata. Ascospores of M. nubilosa also germinated on C. calophylla, but were not observed penetrating the leaf surface. For the first time D. dekkeri conidia and M. marksii ascospores were seen to penetrate stomata of E. globulus on the abaxial surface. No infection structures were observed with D. dekkeri, even though conidia germinated on both surfaces of the leaf. Mycosphaerella marksii formed appressoria on the leaf surface. Further studies are required to establish disease development.
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|Murdoch Affiliation:||School of Biological Sciences and Biotechnology|
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