Oral Presentation Science Protecting Plant Health 2017

The impact of Austropuccinia psidii (myrtle rust) on the endangered Gossia gonoclada in south east Queensland (4005)

Tamara Taylor 1 , Geoff Pegg 2 , Louise Morin 3 , Jacinta Zalucki 1
  1. Environmental Futures Research Institute, Griffith University, Nathan, QLD, Australia
  2. Department of Agriculture and Fisheries, Dutton Park, QLD, Australia
  3. Health and Biosecurity, CSIRO, Canberra, ACT, Australia

Austropuccinia psidii (myrtle rust) is a biotrophic fungal plant pathogen that quickly spread throughout the east coast of Australia after initial detection in 2010. Since its discovery, research has been undertaken to determine the levels of vulnerability of Myrtaceous hosts in Australia. However, to date, little field research has been conducted on some of Australia’s most endangered species, many of which are located within vulnerable rainforest ecosystems that are already under pressure from multiple threatening processes including urbanisation, land clearing, fire and increasing climate variability. This research explores the in-situ impact of myrtle rust on the small fragmented population of Gossia gonoclada (Myrtaceae) - an endangered riparian rainforest tree only found in south east Queensland. Over three years, a categorical scoring method was used to survey myrtle rust disease incidence and severity on G. gonoclada trees within five different sites in Logan City, Queensland. Infection incidence and severity varied among surveyed trees at all sites and among survey years. Our results indicate that variation in climate conditions over the past three years (from flood to drought) have influenced myrtle rust incidence and severity within the population of G. gonoclada. Further analysis is underway to explore the role of host site and leaf phenology in explaining some of the variation in myrtle rust disease susceptibility we see. This research will give us a better understanding of the dynamics of myrtle rust disease in rare plant populations and to identify trees showing tolerance to myrtle rust for future conservation propagation.