About Noogoora Burr
Noogoora burr is one of the most serious and widespread weeds in the world. It is mainly found in areas with high rainfall and a temperate climate but it may also persist in arid environments, where the seeds may remain dormant for years and then take advantage of occasional rainfall to reproduce.
A native of the United States, Mexico and the West Indies, noogoora burr and its subspecies pose a significant threat to the Australian environmental and agriculture industries.
What is Noogoora Burr?
Noogoora burr is erect annual herb that can grow up to 2.5m with two growth forms – either erect single stemmed plants or many branched spreading plants. The leaves of both varieties are dark green, similar in shape to grapevine leaves and around 15 cm in diameter. Stems are blotched or streaked with purple with green flowers in inconspicuous clusters.
Plants produce fruit in the form of a hard woody burr. Each burr has hooked spines around the body and beak-like points at the ends, and contains two seeds, 6-10mm in length. Seeds are spread via clothing or wool and fur of animals, tyres, floating in waterways, movement of contaminated grain and machinery.
With an extensive root system and ability to grow rapidly, noogoora burr is a summer-dominant weed that outcompetes native vegetation, summer crops and pastures. Plants die in late autumn but remain standing, carrying mature burrs for many months.
Where is Noogoora Burr Found?
Noogoora burr is commonly found along roadsides, and in the wetlands and tributaries of river systems. Low lying pastures and crops are also susceptible to infestations, especially those that are low lying or subject to periodic flooding.
What are the Impacts of Noogoora burr?
Noogoora burr plants outcompete native vegetation and agricultural crops, and their burrs and toxins also create a number of unwanted issues:
- wool processors will generally reject wool infested with burrs
- burr spines cause physical damage to stock, people and machinery
- it competes strongly with native vegetation, summer crops and pastures
- plants may carry crop and vegetable diseases
- seedlings are poisonous to stock, particularly cattle and pigs
- it can cause dermatitis and hay fever in humans and animals
What is the Declared Status of Noogoora Burr?
In the Murraylands and Riverland region, noogoora burr is subhect to the following restrictions:
- Prohibiting entry to area
- Prohibiting movement on public roads
- Prohibiting sale of the plant
- Prohibiting sale of contaminated goods
- Requiring notification of
How can Noogoora Burr be Controlled?
Preventing seed set is the most important part of controlling noogoora burr and eliminating infestations. As several germination events can occur between late winter and summer, control should be repeated as often as necessary.
Large populations can be treated with herbicides, cultivation or slashing and follow-up control of smaller populations may include spot spraying, chipping (or hand-hoeing) or inter-row cultivation in crops.
Visit the PIRSA website to find out chemical control options and dosing rates specific to noogoora burr.
For more information about identifying or controlling noogoora burr, contact your local district officer from the Murraylands and Riverland Landscape Board.
What to do if You Suspect a Noogoora Burr Outbreak
In South Australia, noogoora burr is classified as a declared weed meaning that land managers have an obligation to control known infestations.