18 December 2006
Graham Centre targets silverleaf nightshade
Silverleaf nightshade is being targeted by Graham Centre researchers in a project being funded by Meat and Livestock Australia. The Centre views this deep-rooted, summer-growing perennial weed that affects crop and pasture pr oduction as one of the worst in NSW.
Dr Rex Stanton inspects a stands of silverleaf nightshade thriving despite the dry conditions
(Photo: H Wu)
Originating in North America, silverleaf has adapted well to the temperate areas of Australia and is a declared noxious weed in the shires of the major wheat growing areas of NSW.
Project leader Rex Stanton said, once established, silverleaf was very difficult to control and competes for water and nutrients. If left unchecked it could reduce yield of crops grown on infested areas by up to 30 per cent and reduce the carrying capacity of pastures by up to 50 per cent.
"Landholders have estimated that infestations of silverleaf can reduce land values by 25 per cent. A moderate infestation of just one plant per square metre can cause a 10 per cent loss of pasture pr oductivity and a dense infestation of five plants per square metre can halve productivity", he said.
Dr Stanton said most landholders rely on chemical control methods during summer to reduce infestations, aiming to prevent berry-set and deplete root reserves.
According to Dr Stanton,''Silverleaf grows from seed or root stock and if the roots are chopped with discs, this can actually help spread the weed as even a one centimetre piece of root can produce a vigorous plant".
As part of the sliverleaf nightshade project, Graham Centre researchers will also be looking at the role for competitive pastures, biocontrol and allelopathy as additional tools to reduce silverleaf infestations.
Council weed inspectors have identified silverleaf as a growing pr oblem and their advice is to get on top of infestations as soon as you find them.
Noxious Weeds Inspector for Jerilderie Shire Council, Geoff Portbury, said the best way to handle silverleaf was definitely through a concerted, persistent effort. "It's possible to control silverleaf if you keep at it', he said.
"Infestations seem to re-establish from old root fragments even when there has been no sign of plants for a couple of years, so it's important to control plants and also to monitor old infestations."
"We've had cases where large infestations have been reduced to just requiring spot spraying, but you can never be sure how much will re-shoot after the next summer storm', said Mr Portbury.
An information sheet produced by the NSW Department of Primary Industries, Primefact 237, provides more information on silverleaf nightshade. For recommended chemical control options, contact your local council noxious weeds inspector.
Project Contact: Dr Rex Stanton, tel 02 6938 1618, email@example.com
Project background information