Common name: Noogoora bur
Botanical name: Xanthium strumarium
Management category: Eradication
Originally from North and Central America. Thought to have arrived in New Zealand as a contaminant of maize seed, Noogoora bur is one of the most serious and widespread weeds in the world. It was first found as an invasive weed in Noogoora station, Queensland, hence the name.
Why is it a pest?
- Noogoora bur is an agricultural pest. It forms clusters of burs that can stick to animal fur; devaluing wool.
- Seeds are toxic to stock, particularly pigs and cattle.
- It contains chemicals which impede the growth of other plants.
- Causes dermatitis in animals and humans.
- It’s difficult to control - each plant can produce 10,000 seeds per year and seeds can remain dormant in the soil for many years.
Where is it found?
Currently there are a number of Noogoora bur sites in the Bay of Plenty in Te Puke and Papamoa. It is often associated with maize growing and is actively being controlled at all known sites.
Noogoora bur is usually found on arable land often in maize paddocks but will also colonise pastoral land. It may become established on stream margins and suppress native vegetation. Burs float and can be spread by water.
What does it look like?
- Noogoora bur is a fast growing summer annual.
- It grows as a single stemmed plant (e.g. amongst maize) or bushy plant (in the open) up to 2m tall.
- Leaves look similar to grape leaves. They are alternate, large with 3–5 lobes and coarsely toothed, dark green above and paler below, hairy, with prominent purplish veins.
- Stems are rough to the touch and streaked with purple.
- Flowers are seen in summer to late autumn. They are insignificant, green or yellow.
- Seeds are egg shaped burs, 10-25mm long covered in hooked spines with two stout straight spines at the tip. They occur in clusters on the stems and tips of branches. Each bur contains two seeds and a plant may produce 10,000 seeds.
What are the rules?
Noogoora bur is an eradication pest. Eradication pests are present in the region but are limited in their size or extent of infestation. The eradication of these organisms is a feasible and cost-effective solution. The Bay of Plenty Regional Council is responsible for the control of Noogoora bur.
How do you get rid of it?
Noogoora bur is very difficult to control, please do not try to control it yourself. If you think you have found Noogoora bur please contact the Bay of Plenty Regional Council so they can control it.
It is important to ensure that contractors coming onto your property follow correct machinery hygiene and any feed, gravel, seed or soil, brought onto your property is not contaminated.