Disease Risk Assessment

Puccinia psidii (photo courtesy of Dr. Ken Old)

Because of its relative isolation, Australia has remained free of many plant diseases. While quarantine issues are often seen as applying foremost to the protection of agricultural crops, there are a range of important diseases overseas that have the potential to pose a serious risk to our native flora should they be introduced. One such pathogen is Puccinia psidii, a rust that naturally occurs in South America where it attacks a range of hosts in the family Myrtaceae including guava. Members of the family Myrtaceae are extremely important components of very many of Australia's ecosystems as the family includes over 100 genera including Eucalyptus, Melaleuca, Leptospermum and Syzygium. Many eucalypt species grown in South America for their timber have been attacked and among the most susceptible species, death of trees more than 3m high is not unknown.

We are involved in a collaborative project with colleagues elsewhere in CSIRO, in South Africa, and in South America to assess the potential risk associated with this pathogen by screening the susceptibility of samples of a broad range of Australian species from the Myrtaceae to P. psidii. Species for testing are chosen to provide a broad range of coverage of economically important species, species that are rare or endangered, species that form an ecologically important component in native communities, and to give a broad range of the geographic spread of the family in Australia. Because of the potential threat posed by P. psidii, all pathogenicity testing is done in South America.

Scientific Staff: Burdon, Craven