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Grazing management critical for control of summer weeds

While grazing management during late winter or early spring can be used to reduce the negative effects of annual grasses such as barley grass on animal performance and lamb prices, there are benefits of grazing management in the summer. Fire hazard reduction management is one and the other is improving control of summer growing perennial weeds.

New growth from noxious weeds such as silverleaf nightshade can be sheltered by dead annual grasses, which makes herbicide control problematic. Grazing large mobs of suitable livestock in areas where silverleaf nightshade is growing can help trample the dead grass and expose the weed infestation.

Phil Cranney, Senior Land Services Officer Pastures, Central Tablelands Local Land Services, says that, “this type of high intensity grazing has multiple benefits. It can help expose weed regrowth to more sunlight, therefore producing a more even growth pattern. Once livestock are removed and the weed is allowed to regrow, it will allow more efficient herbicide application onto the growing leaf, explained Mr Cranney.

"Stock grazing silverleaf nightshade berries can spread the weed. Graziers should be aware that stock poisoning from alkaloids contained in the weed, particularly ripe berries, may occur. This is a rare occurrence and producers who are concerned about poisoning risks should contact their Local Land Services veterinarian,” said Mr Cranney.

NSW Department of Primary Industries (DPI) principal research scientist, Hanwen Wu, said the critical factor influencing herbicide efficacy is spray droplet contact with the leaf area.

“Spray oils can reduce spray droplet evaporation and wetting agents can aid uptake,” Dr Wu said.

“Using these methods in conjunction with grazing management can greatly improve control of silverleaf nightshade.”

Herbicide, including picloram, glyphosate and fluroxpyr, is registered for the control of silverleaf nightshade. Landholders are advised to read and adhere to the product label and seek advice from an agronomist.

Ongoing DPI research is investigating alternatives to traditional herbicides to address resistance issues in weeds and Dr Wu said there was huge potential to explore the use of eucalyptus essential oil as a bioherbicide.

“We screened 300 eucalyptus species on weeds, including annual ryegrass, barley grass, fleabane, silverleaf nightshade and wild radish, to find that even at low concentrations some eucalyptus oils were able to prevent germination and growth of weed seeds,” he said.

Initial research was funded by the NSW Government Weeds Action Program 2014-2015, with support from Meat & Livestock Australia and the Graham Centre for Agricultural Innovation – an alliance between DPI and Charles Sturt University.

If you need help identify a summer growing noxious weed or advice on your control program, please ask your local council Weeds Officer.

Cowra Council - Kevin Nelligan – 0427 629 237

Cabonne Council - Norm Townsend – 0419 284 991

Mid-Western Regional Council – 6378 2850

For more information on how pastures can be used to compete with weeds please call Phil Cranney, Orange on 02 6363 7888 or Clare Edwards, Mudgee on 02 6378 1700.

Scott Sullivan, Biosecurity Officer Central Tablelands Local land Services, based in Molong, will be talking to farmers about implementing a practical biosecurity plan for their business at the Cowra cropping and livestock update on Thursday 23rd February.

“I’ll be talking about practical ways of reducing the risk of introducing new animal pests, weeds or diseases onto your property. These are easy steps towards implementing a tight biosecurity plan for your business”, said Mr Sullivan.

Also presenting at the Cowra Cropping and Livestock Update will be Tim Nalder, Senior Land Services Officer Central Tablelands Local Land Services. Mr Nalder has been working on the Central Tablelands Regional Strategic Weed Management Plan and will update the landholders present at the Pridham Centre.

For more information about the Cowra cropping and livestock update being held on the 23 February at 12pm - 4pm, please call Phil Cranney 0458 745 478.

Media enquiries: Kylie Krause | 0439608370

NSW DPI weed management guide