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Several species of Ceratocystis have been recorded on Eucalyptus. These include C. fimbriata, C. eucalypti, C. moniliformis and C. moniliformopsis. Of these, only C. fimbriata is known as a pathogen; it recently has been found causing serious wilt diseases in Uganda, Congo and Brazil. This study was undertaken to collect Ceratocystis species, including C. eucalypti, from artificially induced wounds on Eucalyptus nitens near Canberra in southeastern Australia. Trees were wounded in October 2000, and wounds were examined approximately one month later. Ascomata characteristic of a Ceratocystis species were found covering the wounds, and this fungus also was isolated from the wood using carrot baiting. This species of Ceratocystis has hat-shaped ascospores similar to those of C. fimbriata, but it differs from C. fimbriata and all other species of Ceratocystis in that it possesses ascomata with a pyriform base. Comparison of DNA sequences from the ITS and 5.8S rRNA operon confirmed that the fungus from E. nitens in Australia is unique, and we describe it here as a new species, C. pirilliformis.

The woodwasp, Sirex noctilio, and its symbiotic fungus, Amylostereum areolatum, cause extensive damage to pine plantations in the Southern Hemisphere. S. noctilio was first reported from South Africa in 1994. In this study, the population diversity of A. areolatum isolates from South Africa, South America, Australasia and Europe was determined by vegetative incompatibility testing. All 108 South African and 26 South American isolates belonged to the same vegetative compatibility group (VCG). This VCG showed a weak incompatibility reaction with the single Tasmanian and single New Zealand isolates tested. This VCG differed from VCGs from Europe. It also differed from isolates associated with the biocontrol nematode, Deladenus siricidicola, which is produced in Australia. It is concluded that the South African and South American populations of A. areolatum share a common origin.

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