Know your weeds - Serrated Tussock

Serrated tussock, Nassella trichotoma is a prohibited noxious weed in Victoria.

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Plant Identification:

Serrated tussock is a perennial, drought resistant, tussock-forming grass, up to 500 mm high by 750 mm diameter and 250 mm diameter at the base, with a deep, fibrous root system and fine seed heads and seeds that are readily dispersed by wind. It is purple when flowering and straw coloured after the seeds ripen.

Further Identification information can be found at: http://www.serratedtussock.com/idapp

Distribution:

Serrated tussock is found in the south-eastern region of Australia. New South Wales, Victoria, the Australian Capital Territory, and Tasmania all have serrated tussock infestations. Within the Surf Coast Shire, a Serrated Tussock containment line has been defined - see map below. Serrated Tussock is known to be prolific throughout townships, however the Serrated Tussock Working Party

Management options:

Chemical control: The two main chemicals registered for control of Serrated Tussock in Victoria are glyphosate and flupropanate.

It is strongly recommended to include a spray marker dye when spot-spraying Serrated Tussock so you can ensure no plants get missed.

• Glyphosate (trade names include RoundUp, WeedMaster, ) is a non-selective herbicide that kills green, actively growing plants. It is essential to apply glyphosate carefully to minimise non-target damage.

• Flupropanate (trade names include Taskforce, GP Flupropanate, Tussock) is a slow acting herbicide that is predominantly absorbed through the roots and leaves. It can take between 2-12 months to kill the plant, particularly if affected by drought.

Non-chemical control:

• Manual removal (chipping) manual removal can be effective for isolated infestations or those in sensitive areas, but is labour intensive and requires ongoing monitoring to ensure re-infestation does not occur.

• Mulching – mulching has been reported to be an effective control method for isolated infestations. It should be noted that mulching is non-selective and may require non-disturbance of the mulched area as serrated tussock seed can remain viable for up to 7 years when buried in the soil profile.

• Fire – Fire should not be used as the sole management option. While dense serrated tussock infestations will deliver a hot fire at any time of year and may deliver kills of surface soil seed bank, serrated tussock can regenerate rapidly after fire and the majority of actively growing crowns will not be killed.

Other non-chemical control options include:

• Competition

• Shelterbelts

• Slashing

There are advantages and disadvantages to any management option.

• Glyphosate is fast acting and can be used to target other weeds at the same time while spot spraying, however it is non-selective, so overspray or broadacre treatments will leave the area open to re-invasion with tussock and other weeds. As glyphosate is non-residual, it will not impact on the seed-bank in infested areas.

• Flupropanate is a residual herbicide, and will control the growth of serrated tussock for an extended period and as it is selective, tolerant species will be able to re-establish in the area, however Flupropanate can take between 2-12 months to see observable effects as the primary mode of uptake is via roots, so during dry times, chemical uptake can be slow. Long withholding periods for broadacre application can cause pasture management challenges. Lactating stock must not graze pastures treated with flupropanate. Growth rates of some desirable pasture species may be impacted.

• Non-chemical control options can be used in sensitive areas and can be very effective at minimising off-target damage, however are very labour intensive, only identified plants will be managed, and improper management of removed plant material may exacerbate weed spread.

Best practice integrated weed management should involve a combination of control methods used in conjunction with best practice equipment, paddock and livestock hygiene – ensure that any vehicles which have entered infested areas are washed down in a suitable weed wash-down area prior to entering clean areas. Do not allow vehicles or workers which have entered potentially infested areas enter clean paddocks without undergoing wash-down. Limit movement of stock from infested areas to clean areas. Move stock from infested paddocks before serrated tussock goes to seed. When introducing any livestock to a property which may have spent time in infested areas, or are suspected of being contaminated with serrated tussock seed, those stock should be placed in quarantine/holding paddocks.

For further information on serrated tussock management, please visit www.serratedtussock.com or speak to your local agronomist.

Victorian Serrated Tussock Working Party

The Victorian Serrated Tussock Working Party (VSTWP) have been busy with two key deliverables over the past year: an update of the VSTWP Strategy and the completion of the Social Science Research Project. The new VSTWP Strategy runs from 2018-2023 and is the primary guiding strategy for the VSTWP. The Strategy outlines three key objectives:

1. Build community capability to prevent and manage serrated tussock.

2. Reduce the current impact of serrated tussock on affected communities.

3. Restrict the establishment and spread of serrated tussock in Victoria.

The document, which presents strategic actions for the key objectives, can be downloaded by clicking here. The Strategy will be launched in the coming months.

The VSTWP have also released a Social Science Summary Report , "Motivating disengaged landowners to control Serrated Tussock". They believe the report will be beneficial for our stakeholders and the community alike, and that the findings are transferable to many NRM issues and challenges that we face today.

Additional Victorian Serrated Tussock Working Party resources:

Serrated Tussock ID Brochure: http://www.serratedtussock.com/sites/default/files/Indentification%20of%20Serrated%20Tussock%20Brochure.pdf

Serrated Tussock ID app: http://www.serratedtussock.com/idapp

National Serrated Tussock Management Group Best Practice Management Manual: http://www.serratedtussock.com/sites/default/files/Serrated-Tussock-National-Best-Practice-Management-Manual.pdf