FARMERS are being urged to take control of Blackberry and Serrated Tussock this spring.
Serrated Tussock
Nassella trichotoma is a perennial tussock forming grass-like plant that has flowering stems that are erect up to around 90 centimetres, then droop to the ground as the plant matures.
The leaf blade is round and serrations can be felt when running fingers down the leaf from the tip to the base.
Preventing serrated tussock from establishing on your property is the best method of control and is best done in spring, prior to seeding.
Serrated tussock is a prolific seeder with 90 per cent of the plant self-pollinating.
Seed heads of the plant can be carried in the air or along the ground for vast distances.
The majority of Serrated tussock plants will now have seed present, which should be removed to prevent further spread. The Victorian Serrated Tussock Working Party (VSTWP) is asking landholders with seeding Serrated tussock to make reasonable efforts to reduce seed spread to neighbouring areas, as Serrated tussock seeds will blow in the wind late spring.
Removing the seedhead via slashing or mechanical removal is the only way to ensure the seeds do not blow in the wind over the coming weeks, spreading to neighbouring properties.
Seeds can remain dormant in the soil for up to 15 years.
General property hygiene procedures will reduce Serrated tussock, and other weeds, from entering or leaving a property.
Learn to correctly identify Serrated tussock and ensure plants are treated prior to seeding. Be aware of buying in stock feed that could be contaminated with seed – and do not harvest pasture in paddocks infested with Serrated tussock while in seed.
Also, be aware that contractors and machinery are another source of unwanted seed spreading.
VSTWP community engagement officer, Ivan Carter, said, “it’s believed Serrated tussock now covers more than 250,000 hectares of land in Victoria”.
“Large infestations require ongoing management and the integration of a number of control techniques to prevent seeding and further spread across the landscape.”
Serrated tussock management generally includes either physical removal or herbicide application.
Often more than one spray application will be needed to kill all the plants in a large infestation.
Plants must be completely covered with herbicide, as parts that are missed may continue to grow.
Always read and adhere to the directions provided on the product label.
In most situations the sprayed plant should not be removed for at least 6 months after spraying to allow the herbicide time to work. Refer to the product label for directions.
Be aware that dead plants may increase fire hazard.
Before starting herbicide treatment in a new area, all areas treated the previous year should be checked and re-sprayed if necessary.
Incorporation of a compatible marker dye in the herbicide will assist in identifying treated areas and ensure that all plant surfaces are covered. Incorporation of a compatible marker dye may be a legal requirement for complying with a Directions Notice or Land Management Notice.
Protective clothing including gloves and face shield should be worn when working with any herbicide.
Blackberry
Rubus fruticosus aggregate is a serious weed problem across Victoria, and particularly for farmers.
The Victorian Blackberry taskforce was established in 2001 to work with communities and government agencies to control blackberry.
The Taskforces Community Partnership Program covers over 280,000 hectares of both public and private land infested with blackberry.
Controlling Blackberry is generally not a once-of management - it requires ongoing maintenance.
Blackberry can produce root suckers from a depth of at least 45 centimetres, so it is important to remove as much of the root system as possible when using these methods.
Regrowth from crowns, root fragments and seed is inevitable, making follow-up control and site rehabilitation essential.
Combining a range of physical control methods with the strategic use of herbicides is a more reliable approach.
Herbicides are highly effective tools for controlling blackberry, and their use is the most reliable method for achieving local eradication.
There are a large range of herbicides available for blackberry control. The effectiveness and suitability of each herbicide varies depending on your situation and management goals.
Four factors should be considered when controlling blackberry with herbicides:
Most herbicides used for blackberry are absorbed through the foliage, stems or leaves, but some are also absorbed through the roots and can remain active in the soil for some time.
Therefore herbicides will need to be translocated here to kill the plant. Selection of the most appropriate chemical and application technique is important.
The most suitable will depend on a range of site factors such as accessibility, other vegetation, cost, resources and proximity to waterways. Be wary of legislation that may require an accreditation for applying some herbicides.
Always refer to the product label before using any herbicides.
The most common error when spraying Blackberry is to under-spray large bushes.
Such bushes have an extensive surface area comprising the canopy, as well as leaves and canes at the centre of the plant.
Spray operators may see that the outer foliage (canopy) appears wet and decide the plant is sufficiently sprayed. However, the inner parts of the bush may have received virtually no treatment.
Experienced operators ensure that these larger plants get sufficient wetting of the inner leaves and canes.
The optimum time to spray blackberry is when it is actively growing from flowering through to fruiting - usually during December, January, February and March.
However, this may vary between regions and species.
Blackberry can be sprayed before and after these months if conditions are suitable.
Control with herbicides is greatest when plants are actively growing and free of any stress (e.g. moisture stress). This is because plants are more able to absorb and translocate herbicides at this time.
As a guide, look at the tips of the canes for new, soft leaves, as this indicates active growth and shows that the canes are mature enough for herbicide to be applied.
