Gorse moth to be deployed

Sustainability, Environment and Conservation Minister Ian Hunter said Natural Resources SA Murray Darling Basin staff visited Tasmania in February to collect more than 1000 adult gorse soft shoot moths for local release.

“This is an exciting development in our attempts to wipe out this extremely costly and detrimental invasive plant,” he said.

“The gorse moth’s larvae feed exclusively on the new shoots and spines of gorse plants, reducing the number of flowers and seeds they can produce.

“Staff from Natural Resources SAMDB and Adelaide and Mount Lofty Ranges have released the moths at six sites across the two regions, and will now monitor how well they establish here.

“The moths were first released in Tas in 2007 after exhaustive research to prove they would only eat gorse.

“They have since established well in the Tas midlands – which have a similar climate to the Adelaide Hills – and we are planning further releases here to accelerate their spread.”

Gorse is a declared weed of national significance, forming dense, spiny thickets that reduce available pasture, outcompete native vegetation and provide cover for feral foxes and rabbits.

With hard seeds that can remain dormant in the ground for up to 25 years, it can be extremely difficult to eradicate, and it has been estimated that control costs more than $7 million a year.

Mr Hunter said the release of the soft shoot moth would complement existing bio-control agents already in use including gorse seed weevil, gorse spider mite and gorse thrips.

“Long-term biological control will not eradicate gorse, but we hope the combined impact of new and existing control agents will reduce the plants’ vigour and ability to produce seed,” he said.

“They will also make gorse more susceptible to grazing and herbicides as part of an integrated management program.”