Will this fungus stamp out Sea Spurge?

The first releases of the biocontrol agent are underway in south-east Australia with hopes that the fungus, known as Venturia paralias, will reduce the spread and impact of sea spurge (Euphorbia paralias). 

Image: King Island Landcare Group undertaking the first release of the sea spurge biocontrol agent 

Sea spurge is a highly invasive weed - with some of the most severe infestations occurring in Tasmania.  It outcompetes native and threatened coastal plant species, stops native and migratory shore birds from nesting successfully, alters sand movement creating steeper dunes, and releases a latex that can cause skin and eye irritation to humans and pets - not fun on the beach!

🔍Read more about sea spurge in the NRE sea spurge management guide here

None of this is good. So what can we do to purge the spurge? 

Management tactics have involved labour-intensive hand weeding and herbicide application.  This hasn't been successful at keeping sea spurge away because the weed has some sneaky tricks - sea spurge is able to resprout and recolonise with its seeds that travel long distances surfing ocean currents (not cool, dude!) and infesting new areas. 

This has made the prospect of a biocontrol agent very attractive, as it could reduce costs and infestations of the plant.  An application was put forward by CSIRO to release a biocontrol agent on sea spurge, and after significant investigation, in November 2020, the fungus Venturia paralias was approved for release as a biocontrol agent. 

🔍Read the final risk analysis here

Image: Sea spurge impacted by the biocontrol agent. Supplied: Dr. Gavin Hunter

The fungus infects the leaves and stems and is able to spread between sea spurge plants.  The hope of the project is that the fungus establishes widely and reduces the spread of sea spurge, the negative impacts, and reduces the amount of hand pulling required. 

Landcare Community On Board 

King Island Landcare Group have been the first community group to begin utilising the biocontrol agent, with Dr. Gavin Hunter, the CSIRO research scientist managing this project, guiding them through the release. 

Image: King Island Landcare Group spraying plants with spore suspensions of the agent 

The release involved spraying spore suspensions of fresh and dried cultures of the fungus onto sea spurge plants.  The group conducted the first release in the Porky Beach area.

The group are hoping to see a substaintial improvement for biodiversity with the progressive reduction of the number of beaches impacted by sea spurge - yay for the recovery of native habitats, nesting birds and native flora and fauna.

🔍Read more about the release on King Island here

Image: Views aren't bad on the job, King Island Landcare Group

Releases of the sea spurge biocontrol agent are happening through community-led programs. If your group would like to participate in the community-led releases, email Dr. Hunter at [email protected] or if you would like to participate with King Island Landcare email Nathalia Amaral at [email protected] 

Read

🔍Sea Spurge by CSIRO 

🔍Host-specificity testing of the biocontrol agent 

🔍Ecological assessment and testing of biocontrol agent 

🔍Sea Spurge Remote Area Teams 

Watch

Check out Dr. Gavin Hunter speak about the deployment of the biocontrol agent at the 2021 Tasmanian Community Landcare Conf!