Update: Biocontrol of serrated tussock
We are excited to report that our biological control research project has reached a milestone update, which we received from Agriculture Victoria a few weeks ago. The update report highlighted the progress and challenges to date and sets the scene for the upcoming research trials and possible challenges ahead.
The VSTWP contributed $25,000 towards the project in 2019-20, with Agriculture Victoria providing $105,000 and Agriculture New Zealand providing $430,000 and Argentina providing $82,000.
In New Zealand, serrated tussock infests valuable pastoral land in the South Island, with more than 524,000 ha contaminated. The weed also occurs in Auckland, Hawke’s Bay, and Northland. Millions of dollars are spent annually controlling the weed with no end in sight. Agriculture Victoria Research (AVR) has been sub-contracted by Landcare Research New Zealand to assist in investigating the potential of fungi as biocontrol agents against serrated tussock. The key objective of AVR’s research component is to survey and identify potential biocontrol agents from Australia, where previous organisms pathogenic to serrated tussock have been identified.
Millions of dollars are spent annually controlling the weed with no end in sight. Through funding from New Zealand’s Sustainable Farming Fund, Agriculture Victoria Research (AVR) has been sub-contracted by Landcare Research New Zealand Limited to assist in investigating the potential of fungi as biocontrol agents against nassella tussock. The key objective of AVR’s research component is to survey and identify potential biocontrol agents from Australia, where previous organisms pathogenic to nassella tussock have been identified.
The technical report outlines the achievements against Milestone 4, as outlined in the Subproject Agreement for the 2020/21 reporting period.
Progress to date:
- No additional surveys were conducted during the past 6 months, as there was a back-log of over 30 isolates yet to identify from samples collected during July-October 2020.
- 24 further isolates were collected from these samples which originated in Wellington Shire, Vic and Upper Lachlan Shire, NSW
- Of these, 13 isolates are likely to be species that have not been detected in previous surveys including Septoriella spp, Keissleriella sp, Mortierella sp, 2 Fusarium spp, and the putative Geastrum sp. and Wongia sp.
- In total, 95 isolates have been identified from Nassella populations in Australia, these are listed in the full report
- Of these, there are 10 genera that have not been reported from the NZ collections and likely to be some additional species of other genera.
- Further identification of selected isolates using alternative primers has been initiated.
- Host specificity testing on non-target grass species has not yet commenced. This is because a technique for inoculating the target species, Nassella trichotoma, has not yet been perfected.
The VSTWP and Agriculture Victoria will provide updates on the research project, as the results and progress is published. It is hoped that we discover some useful biological control agents, that can slow the spread of serrated tussock and reduce the impacts. This is a long term project and will likely take a number of years to complete.