Wandering trad (Tradescantia fluminensis) is an herbaceous groundcover native to South America that has become a significant environmental weed of temperate regions of Australia, with hotspots of invasion in moist forests of eastern NSW, south east Queensland and the Dandenong Ranges region of Victoria.

Infestation of wandering trad in the Dandenong Ranges, Victoria.

The leaf-smut fungus Kordyana brasiliensis was first released in the field in Australia for the biological control (biocontrol) of wandering trad in March 2019. This agent was discovered on wandering trad during surveys in Brazil performed by researchers at the Universidade Federal de Viçosa. This exploratory research was part of the biocontrol program for this weed in New Zealand, led by Landcare Research.

CSIRO has been involved in research on wandering trad biocontrol since 2014. The risk assessment that was the basis of the application to seek permission for the release of the leaf-smut fungus in Australia was financially supported by CSIRO and the Australian Government’s National Environmental Research/Science Programme administered by the Department of the Environment and Energy.

The leaf-smut fungus Kordyana brasiliensis released in Australia in March 2019.

Research to develop optimal protocols for field release of the fungus and subsequent releases in the Dandenong Ranges region of Victoria in partnership with the community was co-funded by CSIRO and the Australian Government under the Improving Your Local Parks and Environment Program administered by the Department of Industry, Innovation and Science and supported by the Community Weeds Alliance of the Dandenongs. These activities were part of a broader project seeking biocontrol solutions for sustainable management of environmental weeds, which also includes Cape ivy (Delairea odorata) and angled onion (Allium triquetrum) that ended in October 2020.

A new project from July 2020 to June 2023, co-funded by CSIRO and the New South Wales Government through its Environmental Trust, will be facilitating stakeholders’ releases of the fungus across the range of wandering trad in New South Wales. The project will also monitor the impact of the fungus on the weed and flow-on indirect impact on other vegetation at several sites during that period.