French breakthrough may help CSIRO stop invasive sea spurge weed in Australia

Australian scientists hope to combat the invasive Sea Spurge with its natural enemy, a fungus.

Australian scientists hope to combat the invasive Sea Spurge with its natural enemy, a fungus. Photo: CSIRO

It’s a story that had its roots in France more than a decade ago.

When CSIRO scientists based in Europe discovered some sick plants on the Atlantic coast of France in 2008 they knew they were on to something.

It was a significant breakthrough for researchers who had been trying to combat the highly invasive coastal weed Sea Spurge in Australia.

What the scientists in France had discovered was the weed’s natural enemy, a fungus called Venturia paralias.

“The fungus that was isolated in France was a parasite that infects the leaf, and then moves to the stem and under laboratory conditions kills it,” CSIRO scientist Dr Gavin Hunter told AAP.

Thirteen years on the fungus has been cultivated in an Australian laboratory, and shown to be highly effective at killing Sea Spurge.

And now it’s about to be released into the Australian environment.

“The release of the agent into the Australian environment is not going to completely wipe out Sea Spurge, but we hope it will reduce the density of the weed making the management of Sea Spurge becomes easier,” Dr Hunter said.

“Over two years of testing we found it doesn’t pose a risk to native flora or fauna, it was really specific to sea spurge.”

Highly invasive, Sea Spurge has been known to invade coastal ecosystems from Geraldton in Western Australia, along the southern coastline, and to Forster on the mid-north coast of NSW.

The weed disrupts native species including endangered shorebirds like hooded plovers, little terns and pied oystercatchers that use open sand for nesting.

But the removal of Sea Spurge by humans exposes workers to toxic white latex, which can cause skin and eye irritations, another reason why the search was on for a scientific alternative.

“Sea Spurge or Euphoria paralias competes with native flora on dune ecosystems, and makes it difficult for shore birds to nest, as well as competing with native flora” Dr Hunter told AAP.

Sea Spurge was first identified in Western Australia in the 1920s, and was likely introduced from Europe.

The weed is known to prevent the natural movement of sand and alter the dune structure.

A prolific seed producer, a mature Sea Spurge plant can produce up to 50,000 seeds per year.

Sea Spurge can grow anywhere on the beach front from the high-water mark, taking over sand and native dune vegetation.

Whether the fungus can be as effective in the natural environment as it has been in the lab is about to be put to the test.

Scientists have just begun releasing the bioagent onto the coastlines of Tasmania, and will eventually expand the program to Victoria.

They hope they can combat the weed in the southern states before the ocean currents send the seeds north.

The scientists will work with community groups and landholders to release the fungus onto Australia’s southern coastline.

Sea Spurge Remote Area Teams (SPRATS) spokesperson Dr Jon Marsden-Smedley will take part in the first release of the fungus in Tasmania.

He’s excited to have another tool to help manage the weed infesting the beaches.

“CSIRO has provided comprehensive guidelines for our volunteers to release the fungus and inoculate Sea Spurge plants where it is needed most,” Dr Marsden-Smedley said.


Topics: CSIRO
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