Controlling serrated tussock plants as soon as they appear and before they seed will limit the spread of this weed. Early intervention is the best way to avoid heavy production losses and the high cost of control at a later date.
Why Is It Bad?:
Serrated Tussock has a low feed value and a lack of palatability to sheep and cattle, it is hard to identify when not seeding. It is extremely drought tolerant and infests country of both high and low productivity. Serrated tussock seeds prolifically, whole seed heads are carried long distances by wind. It is difficult and costly to control, particularly on non arable land. Serrated Tussock becomes a monoculture threatening the biodiversity and ecology of agricultural and non agricultural systems.
Serrated tussock leaves are tightly rolled, narrow, stiff and upright. They have small serrations that can be felt when the leaf is drawn between the fingers. Although the common name 'serrated tussock' suggests that these serrations are a key feature of the weed, reliance on serrations alone for identification can be misleading as other tussock grasses can have similar serrations.
Serrated tussock generally flowers during mid to late spring, and the seeds develop in early to mid summer. The time of flowering is variable from year to year, depending on seasonal conditions.
The seed head of serrated tussock is a multi branched seed head up to 35cm long. At each junction of the seed head, there are two of three branches lading to a single seed on each branch or another set of small branches with single seeds. Seed is encased in reddish brown or purple bracts and is 1.5mm long, with a ring of white hairs at one end and a twisted awn 25mm long at the other.
Serrated tussock has a deep fibrous root system. This root system also makes serrated tussock more difficult to pull out than other tussock grasses of similar size.
Chipping is also a suitable method to control individual plants scattered throughout clean paddocks. Isolated tussocks can be chipped with a mattock all year round, preferably before they seed. When conditions are wet, soil clods should be removed from the roots to prevent survival. Excessive soil disturbance can encourage germination of seeds, the scattering of pasture seed and fertiliser in the disturbed area is an effective means of quickly revegetating to provide competition.
A number of herbicides are registered for the control of serrated tussock in NSW and they are available under generic names. The most widely used herbicide contain the active ingredients glyphosate or flupropanate. Herbicide alone cannot be relied upon forlong term control. Competitive desirable pasture species should be encouraged to prevent reinvasion by serrated tussock in the longer term.
Tussocks chipped in full flower should be removed from the paddock and disposed of by burning.
Slashing & Cutting:
Small infestations can be kept at bay through improved pasture competition, by regular fertiliser applications and grazing rests, which allow desirable species to increase in size and become more competitive. Serrated tussock seedlings are weak competitors and will only take hold in the absence of other competition.
Cultivation & Scalping:
In areas of low soil fertility and low rainfall afforestation can be an effective means of controlling serrated tussock in the long term. Afforestation should be coupled with techniques such as herbicides and or chipping to control serrated tussock spread and seed production prior to effective control by the tree canopy.Flupropanate can be used with minimal damage to juvenile Acacia species or Eucalyptus species. Details of Afforestation can be obtained from Department of Industry and Investment.