Northern Territory. Department of Environment and Natural Resources
Weed Management Fact Sheets; E-Journals; PublicationNT; Weed Management Fact Sheets
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Weed management; Prickly acacia; Acacia nilotica
Northern Territory Government
Weed Management Fact Sheets
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Northern Territory Government
T: 08 8999 4567 | E: email@example.com | W: www.nt.gov.au/weeds Habitat and distribution Prickly acacia is native to the tropics and subtropics of Africa through to Pakistan, India and Burma. It was deliberately imported into Australia as a shade and fodder tree prior to the 1960s. Prickly acacia is now distributed from Cooktown (north Queensland) to the New South Wales border and from Bowen (east Queensland) to Western Australias Kimberly region. The transportation of cattle is believed to have contributed to the wide dispersal. Prickly acacia has established across approximately 7 million hectares in Queensland. The first recorded outbreak in the NT was in 1981 as a single plant on the roadside of the Barkly Highway. Infestations in the Northern Territory generally do not exceed low density (1 to 10% coverage), however plants are present throughout the Barkly, Katherine and Alice Springs regions. Control work has significantly reduced density levels and spread, however continued collaborative management is essential. Outbreaks in Adelaide River and Batchelor have been successfully eradicated. The Victoria River District has one of the most significant infestations. Monitoring will continue in all susceptible areas. Preventing spread of Prickly acacia By implementing the following recommendations potential spread can be significantly reduced: map infestations before control to enable the development of a coordinated management strategy control minor infestations, isolated trees or seedlings first prioritise control along bore drains, creeks and dams to reduce spread exclude stock where mature pods are available, incorporate strategic fencing to contain infestations and quarantine stock when moving from infested paddocks to clean paddocks (seeds may take up to 6 days to pass through an animal) do not overgraze - a healthy stand of grass will reduce the establishment of seedlings ensure stock imported from affected areas in QLD are quarantined upon arrival to the Northern Territory or your property. Monitor quarantine area or paddock for emerging seedlings Prickly acacia control Non-chemical control hand grubbing (small plants) blade ploughing, stick raking and chaining (for larger plants or infestations, cutting the root at least 30cm below the soil surface can be effective) for larger trees greater than 40mm trunk diameter, chain pulling is more effective. Chain pulling has been successfully used on established, dense stands of prickly acacia, especially if dry or drought conditions are prevailing fire is useful for mass seedling control if there is a sufficient fuel load* It is vital that follow up works are carried out to control seedling recruitment and regrowth after a site has been treated. If left uncontrolled, seedlings and regrowth may develop into a bigger problem than the initial infestation. Control should preferentially be undertaken prior to seed drop. In Queensland significant research has been carried out on biological control options for prickly acacia. Tip boring moths, seed feeding beetles, leaf feeding beetles, caterpillars and bark/wood-feeding insects have all been released with little success. Research is ongoing. Infestations in the Northern Territory are not dense enough to require or enable biocontrol. A range of chemical and mechanical options are suitable for prickly acacia control. * Any management incorporating burning must be in accordance with the Bushfires Management Act 2016 and Fire and Emergency Act 1996. Please contact your local fire station for permits to burn.