Biocontrol for African boxthorn pest weed released

The Illawarra Shoalhaven Joint Organisation (ISJO), NSW National Parks and Wildlife Service (NPWS) and the Illawarra District Weeds Authority (IDWA) are excited to be participating in an Australian-first release program of a biocontrol agent to help control African boxthorn, based on research undertaken by the CSIRO.

African boxthorn is a Weed of National Significance (WoNS) and poses a serious threat to our local agriculture systems and natural environment.

It is a thorny shrub with red berries and purple flowers. Introduced to Australia from South Africa in the mid 1800’s as a hedge plant it has since spread from old homesteads and urban areas. African boxthorn berries, leaves, stems, and roots are toxic to humans, whilst its large thorns can injure livestock. It can invade pastures and remnant bushland and form impenetrable thickets that block access for vehicles livestock and people. It can also harbour pest animals. 

The IDWA has identified a priority infestation of African boxthorn on Minnamurra (Stack) Island, within Killalea Regional Park where the initial release will take place. This infestation is acting as a seed source for spread to surrounding areas.

The biocontrol agent, a rust fungus, has undergone stringent testing to ensure it does not pose a threat to non-target plants and will be released on Minnamurra Island by NPWS staff where it is hoped the agent will establish and reduce the risk of further invasion by this problematic weed.

The release of the African boxthorn agent follows on from another successful CSIRO biocontrol program on Wandering Trad that commenced in March 2019.

More information about CSIRO’s research program can be found here: https://research.csiro.au/african-boxthorn/progress-rrnd4p-rnd-4/