Property owner alert to Caltrop after recent rains

Agricultural property owners in the Northern and Yorke region are encouraged to take proactive measures to control Caltrop (Tribulus terrestris) after recent rains.

The plant is a declared weed in South Australia and is most abundant on light sandy soils but will grow on almost any soil type in the Northern and Yorke region.

It germinates after rainfall in late spring and summer as soil temperatures increase.

There is a succession of germinations throughout summer following each rainfall event, and heavy rain across the region in recent days is anticipated to spark rapid germination.

Caltrop is a flat annual herb with stems spreading out for up to two metres from a woody taproot.

Its fruit consists of a woody burr with sharp, rigid spines, which splits into segments when ripe. Each segment has four hard spines; two spines are long and two shorter.

More than 1,000 seeds can be produced by a single plant and seed can remain viable for many years.

It will readily attach to the feet of animals, vehicle tyres, rubbersoled shoes and almost any object that is placed on it.

It is toxic to stock and can cause nitrate poisoning, photosensitisation and staggers.

It is of nuisance to urban residents as they impact upon people and pet movements and is well known for its damage to bicycle tyres.

Preventing the spread of Caltrop is the best control measure.

Clean machinery and vehicles before moving out of areas of Caltrop infestation. If you have paddocks infested with Caltrop, minimise stock movements from these areas and treat with a registered chemical for broad-acre control.

For further information Contact Landscape Rangers in the Upper North, Lower North and Yorke Districts.

Contact details

• Lower North – Landscape Team Leader: Grant Roberts 0428 842 492
• Upper North – Landscape Team Leader: Kevin Teague 0428 990 675
• Yorke Peninsula – Landscape Team Leader: Ken Rudd 0427 280 820