Sea spurge grows at Jervis Bay in New South Wales

A sandy beach covered in toxic sea spurge plants can quickly make a visit to the beach unpleasant. Sea spurge, Euphorbia paralias, is a major plant invader of our beautiful southern beaches and it continues to spread. 

The plant causes environmental problems along many beaches, outcompeting native plants and changing natural patterns of sand movement. It’s also a worry for endangered shorebirds that use the open sand for nesting.  

Our scientists have found a fungus, Venturia paralias, that is highly specific to sea spurge. This fungus was recently approved for release as a biocontrol agent of the plant in Australia. We hope it will help manage this weed that invades beaches from Perth in Western Australia to the mid-north coast of New South Wales, and around Tasmania’s coastline.  

Our research scientist, Dr Gavin Hunter explained that classical biocontrol is where we use the weed’s own enemy against it. To find a plant’s natural enemy with biocontrol potential, we need to travel to the native home of the plant and perform extensive field surveys. 

“We’re always excited when our research leads us to find promising biocontrol agents to manage major weeds, especially toxic ones like sea spurge,” Gavin said.

“We’ll be able to use the fungus we found on sea spurge alongside existing management practices to keep the weed at manageable levels.”  

Managing sea spurge done by fungi

This fungus (Venturia paralias) is native to Europe. It was first collected in France from diseased sea spurge plants. Studied extensively, the fungus infects the leaves and spreads to the stems where it causes lesions. Additionally, severe infections can lead to stem collapse. Our research found the fungus is highly specific towards sea spurge. Based on our results, the fungus was approved by the Department of Agriculture, Water and the Environment (DAWE) for release in Australia.  

The high humidity of coastal environments should favour the growth and sporulation of the fungus. Also, prevailing winds should contribute to its spread along the coastline so that it can infect other sea spurge plants. We hope that once released at several sites, the fungus will readily establish and gradually cause disease on sea spurge plants and reduce their ability to produce seeds in the long term. 

Spores of the biocontrol fungus, Venturia paralias

Citizen scientists, we want you 

Severe infestations of sea spurge occur in Tasmania and Victoria. These infestations are the likely source of seeds that spread via ocean currents and invade beaches in New South Wales. So to help stop the spread, the New South Wales Government through its Environmental Trust has committed to financially support releases of the recently approved biocontrol agent in Tasmania and Victoria. 

Keen to participate in a community release of the biocontrol agent? Here’s how you can get involved. If you are in Victoria or Tasmania and identify an infestation, you need to obtain approval from the land manager or owner of the site to make a release. Once you have approval, contact us.  

When sites become selected for release, we will send you a kit. The kits will contain the fungus and an explanation of how to inoculate the sea spurge plants with the biocontrol agent. Lastly, we encourage you to inspire others to take part, including existing volunteer groups.

Little penguins returning to their nests.