Abstract
Alcoa of Australia is committed to reintroduce 80% of the jarrah forest plant. species back onto rehabilitated bauxite mines in south western Australia by 1997. It has been observed that plant deaths do occur on these mines. The aim of this project was to determine if plant pathogens were responsible for these deaths. Healthy, sick and dying plants were sampled over a 5 week period initiated in February 1993. The following isolates were obtained from 19 plant species: 25 Fusarium spp., 11 Botryosporium sp., 8 Bdtryosphaeria ribis, 5 Cytospora eucalypticola, 6 Phoma spp. isolates, 5 Gelasinospora spp., 4 Diaporthe sp., 4 Pestalotiopsis sp., 3 Phonzopsis spp., 1 Dichomera eucalypti, 1 Phytophthora sp., 1 Monochaetia sp. and 1 Botrytis cinerea isolate. Many other fungi were isolated but could not be identified. Not all isolates were tested in glasshouse or field pathogenicity trials. Two B. ribis isolates were lesion forming in glasshouse trials. Gelasinospora, C. eucalypticola, Botryosporium and D. eucalypti were not lesion forming but were reisolated from the wound tissue, indicating that these fungi had the potential to be pathogenic. Field trials initiated in June (winter) (duration of 3-6 weeks) showed 3 B. ribis, 1 C. eucalypticola, and 1 Phoma sp. isolates to be lesion forming. Many isolates were not lesion forming including B. ribis, C. eucalypticola, Diaporthe, Botryosporium, Phoma, Phomopsis, D. eucalypti, and Fusarium but were reisolated from wound tissue, indicating they have the potential to be pathogens. Environmental conditions were felt to be responsible for the lack of lesions in the plants and it was recommended that these pathogenicity tests be repeated in summer, when environmental conditions are likely to be conducive to disease.
