A beetle which has significantly reduced problem weed silverleaf nightshade in South Africa has recently arrived in Australia and will now be studied for release under a nationally-funded research program.
SAGIT Chairman Michael Treloar said the research project is an exciting opportunity to work with the South Australian government in finding a long term solution to combat the noxious weed.
“In South Australia alone, up to 200,000 hectares of land are infested with silverleaf nightshade,” he said. “The beetle has shown great results in South Africa and we are looking forward to working with PIRSA to investigate.”
Primary Industries and Regions SA (PIRSA) Senior Research Scientist Dr John Heap is leading the investigation of the leaf-eating beetle after studying herbicide and other control treatments for the past 20 years.
Dr Heap said silverleaf nightshade is a difficult weed to control as herbicide treatments often work to remove the plants at surface level but will not effectively attack the roots and so the weed returns.
“Silverleaf nightshade is a deep-rooted perennial plant that is widespread across the wheat belt areas of New South Wales, Victoria and South Australia. Once established, silverleaf nightshade is difficult to eradicate,” he said.
“The beetles live underground in the soil just beneath the plants and come out when the weather is suitable for the silverleaf nightshade to grow. At this stage, the beetle has only been seen to eat silverleaf nightshade, however, we have lots of related native species of plants in Australia they don’t have in South Africa. We will undertake at least three years of highly controlled trials in quarantine to see if the beetles eat these native species or horticultural plants.”
The project is part of Round 1 of the Federal Government’s Rural Research and Development for Profit funding which aims to improve farm-gate productivity and profitability and deliver real outcomes for Australian farmers.
The project aims to improve the control of six national priority agricultural weeds (parkinsonia, parthenium, blackberry, silverleaf nightshade, cylindropuntia, gorse). Success will be achieved by fast-tracking delivery of eight biocontrol agents to producers and is expected to reduce weed competition and herbicide use.
SAGIT Project Manager Malcolm Buckby, PIRSA Researcher Dr John Heap, SAGIT trustee Ted Langley and SAGIT Scientific Officer Allan Mayfield at the trial site near Keith investigating control options for noxious weed silverleaf nightshade. Photo: Bridget Penna