Plan springtime serrated tussock control now
12 August 2016
Many pastures are starting to show increased pasture growth and development with the warming weather. Unfortunately this is also the case for many noxious weeds such as serrated tussock.
South East Local Land Services Pastures Officer, Jo Powells advises spring serrated tussock control needs to be carefully planned and targeted.
“The actions taken should be based on the density of the weed and its location within the broader landscape,” Ms Powells said.
“Regular paddock checks should allow you to identify and map out areas of heavy infestations, scattered clumps and isolated tussock plants. Priority areas for tussock control should include:
- any isolated plants within ‘clean’ or relatively weed free paddocks, boundary and/or high elevation paddocks with downwind neighbours
- paddocks where tussock control has been undertaken in previous years
- paddocks identified for future pasture improvement.
“Serrated tussock begins to flower from mid to late spring, however early spring is the last opportunity to spray to prevent seed production when using the herbicide flupropanate (trade names include Taskforce, Tussock to name a few) which is commonly used for serrated tussock control. There are two key things to note regarding this chemical.
“Firstly, it is predominantly absorbed through the plant’s root system and accumulates in the growing points of the plant. This takes time and under some conditions it can take several months for a serrated tussock plant to begin to die.
“By mid- August, using flupropanate alone may not kill the tussock plant before it begins to set seed. Serrated tussock seeds can generally germinate over a three year period from when they are first produced, so preventing seed set each and every year is important for achieving long term control of the weed, Ms Powells said.
“If spraying from mid-August onwards it may be best to use either a mix of glyphosate and flupropanate or glyphosate alone to kill the tussock plant whilst also preventing seed set. Note that glyphosate is a non-selective herbicide that will kill many desirable as well as undesirable plant species so hence must be used responsibly.
“Always read the herbicide label for directions on application rates, timing etc. Contact your South East Local Land Services agricultural production adviser, local weeds officer or private agronomist for further information.
“The second point to consider is the residual nature of flupropanate. This characteristic can provide some longer term herbicide activity that can kill new tussock seedlings germinating from the soil seedbank. However, it should be noted that this residual activity is not indefinite. The herbicide label will indicate the approximate residual activity period (plant-back or reseeding interval) but it is generally described as being present until at least 100 mm of leaching rainfall (or irrigation) has fallen on the sprayed site.
“When using any herbicides for weed control always observe the grazing withholding periods and slaughter intervals on the herbicide label and don’t forget to keep accurate spray records.
“Herbicide use is only one of many control options for serrated tussock. Using a combination of control options including hand chipping, good paddock hygiene, slashing (to prevent seeding), burning and maintaining a competitive pasture will all help. Developing an integrated weed control plan will assist in the planning of long-term weed control activities for the best success.”
South East Local Land Services runs workshops and field days throughout the year that assists land managers with their weed control activities. Keep an eye out for events in your local area this spring.
Media contact: Jo Powells, 02 6452 1455 or 0429 785 986