Section 5 Case studies - Weeds Australia

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<strong>Case</strong> Study 7 Managing serrated tussock in conservation native grasslands Summary ACT Parks, Conservation and Lands use spray “lances” to selectively target individual serrated tussock plants with herbicide minimising damage or spray drift to surrounding native species. Although painstaking, the approach has produced excellent results, successfully reducing serrated tussock infestations in conservation areas. The problem Serrated tussock is identified as a threatening process under the NSW Threatened Species Act. It can invade native grasslands, especially those with sparse ground cover. The weed can quickly outcompete native species, dramatically reducing the biodiversity of an area and forming a monoculture. Plants begin to produce high volumes of wind-dispersed seed two years after germinating, enabling a rapid rate of spread. Serrated tussock control is now recognised as one of the highest weed control priorities in the ACT. ACT Parks, Conservation and Lands (ACT Parks) staff and land holders are encouraged and directed to treat new serrated tussock infestations as soon as they are discovered. The approach When controlling serrated tussock in lands managed for the conservation of native grassland, ACT Parks staff aim to minimise damage to off-target species and prevent serrated tussock seed set. The techniques they employ are: Targeted application: ACT Parks staff spot spray glyphosate using a “lance” that gets the herbicide to the crown of each serrated tussock plant and allows thorough coverage of all leaves while minimising wind and operator “overspraying”. They use glyphosate at 1% as the principle herbicide, increasing its efficacy during dry weather by adding a “non-ionic surfactant/ mineral oil” to the glyphosate mix. Key messages • Widescale, careful and strategic spot spraying of serrated tussock using a “lance” does less damage to beneficial species promoting more competition and less serrated tussock re-invasion. • Addition of the spray adjuvant “a non-ionic surfactant/mineral oil” to glyphosate mix has improved serrated tussock kill during dry times of the year. • A key to long-term success is diligent and routine follow up. • Serrated tussock management in conservation grasslands is expensive and needs ongoing community support to maintain the required resources. Follow up: Staff carry out regular and strategic monitoring of treated areas, spot spraying all newly detected plants. They believe it is critical for the weed’s long-term control to ensure that no serrated tussock be allowed to produce seed. Glyphosate spot spraying of serrated tussock using a lance to reduce off target damage. Steve Taylor 104
Results of careful glyphosate spot spraying of serrated tussock. Native Tall Speargrass Dead Serrated Tussock Native Tall Speargrass Steve Taylor ACT Parks staff do not recommend widespread use of flupropanate in conservation grasslands. Flupropanate can cause damage to beneficial grass species such as wallaby grass (Austrodanthonia) and Microlaena. The exception is in areas where the main native grass is Red-leg Grass, which is tolerant to low rates (1.5 L/ha) rates of flupropanate. The result ACT staff have succeeded in limiting the spread of existing serrated tussock infestations at Gungahlin and Jerrabomberra districts in the ACT. They have also managed to reduce the size of the main infestations while increasing the dominance of native grasses, for example Redleg Grass, Hairy Panic and Tall Speargrass. The future The interaction of more frequent drought with overgrazing has increased the number of areas around the ACT that have sparse ground cover—prime territory for the invasion of serrated tussock. To ensure that serrated tussock infestations do not become even more critical, ACT Parks believes it is imperative that all new infestations, whether on public or private land, are quickly and continuously suppressed. ACT Parks, therefore, accepts that part of its role is to educate the wider community about serrated tussock and its control. Serrated tussock control requires the long-term financial commitment of the ACT government and the development of initiatives that may even include kangaroo culling to reduce grazing pressure on native pastures. Before (2005) (left) and after (2007) (right) photos of spot spraying serrated tussock with Round-up Biactive at Jerrabomberra Grasslands Nature Reserve, ACT. The weed management here has shifted the area from serrated tussock dominant to tall speargrass dominant - so quite a success. Rigorous follow-up is the key to success. Steve Taylor 105
Page 1 and 2: Section 5 Case studies 1. Changing
Page 3 and 4: Hand pulling: All farm vehicles are
Page 5 and 6: Case Study 2 Pasture management Sum
Page 7 and 8: Case Study 3 Controlling serrated t
Page 9 and 10: Case Study 4 Tackling serrated tuss
Page 11 and 12: Tea tree being used to out-compete
Page 13 and 14: Urban serrated tussock infestations
Page 15 and 16: Case Study 6 Cooperative approach b
Page 17: The result According to Council, as
Page 21 and 22: The result No serrated tussock plan
Page 23 and 24: Case Study 10 Serrated tussock stra

Section 5 Case studies - Weeds Australia

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