Title: Workshops present latest control strategies for silverleaf nightshade
[NSW Department of Primary Industries 22 Nov 2010] -- The latest management recommendations for the control of the perennial, summer-active weed silverleaf nightshade are currently being delivered to farmers and advisors in South Australia, Victoria and NSW. Attending farmers and advisors are being encouraged to take an integrated approach that targets both the silverleaf nightshade seedbank and the extensive root system (rootbank). The workshops, which run until late March, present new control strategies developed from a five-year research project led by Dr Hanwen Wu of the EH Graham Centre for Agricultural Innovation, funded by Meat and Livestock Australia.
Dr Rex Stanton, research scientist with the project, said positive outcomes from the workshops included a greater awareness of the potential threat and cost of this persistent weed, as well as the informal farmer discussion that highlighted local success stories.
He said, if left unchecked, silverleaf nightshade could infest an estimated 400 million hectares of Australian crop and pasture land.
Silverleaf nightshade originated in central or southern America and was first introduced into Australia in the early 1900s.
It has adapted well and by the1960s could be found across soil types and climatic zones from the northern slopes of NSW to the Mallee regions of South Australia and Victoria, reducing productive capacity and ultimately land values.
“Our research has concentrated on the biology and ecology of silverleaf nightshade and identified key stages of the plant's life cycle that must be targeted to eradicate existing infestations and to reduce the risk of spread,” Dr Stanton said.
Silverleaf nightshade grows from seed and root fragments and the clear message from the research is that effective eradication must take on a dual action approach that hits both the seedbank and the rootbank."
While most weed control programs focus on stopping seed set and running down the seedbank, the extensive root system of silverleaf nightshade plants is a major source of new growth.
Preventing seed set is really only doing half the job," said Dr Stanton.
"The first action aims to prevent seed set and must occur in late spring or early summer before green berries form, and could include a grazing, slashing and/or herbicides.
Action targeting the rootbank comes later in the season. Research has shown that herbicide impact on the roots is greatest when the plant begins to shutdown in autumn."
Dr Stanton said farmers and advisors attending the workshops were adamant that a successful silverleaf nightshade control program must be a long-term commitment that includes mapping and containing infestations, with a concerted program of dual action strategies, followed by monitoring and spot spraying.
"A concern among farmers attending the workshop is that managers of farm and crown land who are not familiar with silverleaf nightshade underestimate its damaging potential.
"As one farmer warned, even small infestations should not be ignored," Dr Stanton said.