Farmers Warned to Watch Out for Herbicide Resistant Serrated Tussock

Landholders have been warned to watch out for herbicide resistance in serrated tussock, and seek advice on alternative control strategies as soon as possible to avoid an explosion in this expensive, noxious weed across the Central Tablelands.

Serrated tussock (Nassella trichotoma) is an invasive perennial grass weed that can have devastating consequences for both agriculture and the natural environment. Making the situation even worse is the growing problem of herbicide resistance.  

Resistance to the chemical, flupropanate, in serrated tussock plants was first identified in Victoria in 2002 and has now spread to NSW with confirmed infestations in several locations from Goulburn to as far north as Armidale.

“We need farmers and other land managers to be alert for signs of resistance and to implement alternative control strategies before that resistance becomes widespread in the plant population,” said Phil Cranney, Senior Land Services Officer - Pastures with Central Tablelands Local Land Services.

“If the whole community works together, we have a chance of reducing the impact on farm income and the environment,” explained Phil.

Research from Tony Cook, Technical Specialist Weeds with NSW DPI, has demonstrated that a small range of herbicides are showing potential as alternatives to flupropanate for the control of serrated tussock. The new treatments are likely to become legal for use on farm with the introduction of a ‘minor use permit’ later this year.

“There’s a lot of work to be done now in testing new combinations of herbicides. Even when we find new solutions selection pressure will inevitably develop on the remaining herbicides we have available, so we will have to be more vigilant in detecting new types of resistance, and responding quickly before problems spread,” said Mr Cook.

Serrated tussock is very similar in appearance to many Australian native grasses but has very little nutritional value for livestock. Animals will eventually starve to death if only grazed on serrated tussock.

The weed can infest both native and improved pastures resulting in a dramatic loss in carrying capacity and reduced land values. It can also transform diverse native ecosystems into a serrated tussock monoculture. The reduction in biodiversity is a serious threat to native fauna and flora that inhabit infested areas.

All landholders have a legal obligation to control serrated tussock on their property. Landholders should always use the proscribed label rate when applying chemical for the control of serrated tussock.

For more information about serrated tussock and herbicide resistance contact your local weeds officer:

• Mid-western Regional Council - Sean Richardson:  02 6378 2935
• Cabonne Council – Norm Townsend:  02 6392 3202
• Upper Macquarie County Council – Laurie Waddell:  02 6338 2875
• Cowra regional council – Kevin Nelligan:  0427 629 237
• Orange City Council – Roger Smith:  02 6393 8025

For information about reducing the spread of noxious weeds by promoting a healthy and competitive perennial pasture, please contact Clare Edwards in Mudgee on 02 6378 1700 or Phil Cranney in Orange on 02 6363 7888

If you would like help differentiating Serrated Tussock from native grasses that are similar in appearance, contact your local weeds officer or your nearest Local Land Services office on: 1300 795 299.