Don't let Caltrop hitch a free ride around our region

20 November 2020 

In addition to a Netflix binge this weekend, your time could be well spent tackling prickly pest weeds like Caltrop (Tribulus terrestris).

South Australia’s current COVID-19 restrictions coincide with the germination of this declared weed, which spreads like a virus with its spiky burrs transported via shoes, tyres and stock.

Landscape Officer Ben Page from the Northern and Yorke Landscape Board said now is the best time to stop the spread of this opportunistic weed.

“Caltrop is very good at hitching a free ride,” said Mr Page. “Our sheep, shoes and vehicles unknowingly pick up the thorny hitchhikers and drop them off at new sites ready for germination the following year.

“With each Caltrop plant producing about 1000 seeds, pulling out the newly-germinated plants before they get a chance to set seed is the best line of defence.

“And right now the plants are only small, so they’re easy to pull out by hand or can be controlled with a low rate herbicide.”

Ensuring machinery is clean and minimising stock movement from Caltrop-infested paddocks are also important control measures. For areas already overrun with Caltrop prickles, Mr Page recommends using carpet or rubber-soled shoes to pick them up.

“You can walk around your property collecting burrs in your thongs or better yet, roll out the red carpet for Caltrop! Spread some old carpet on an infested area, walk all over it and then put it in the bin,” he said.

It is also a prime time for other burr weeds to take hold, such as Innocent weed and Khaki weed.

Innocent Weed is a pest of pastures and irrigated horticulture crops, with its burrs injuring stock mouths and guts and contaminating fodder hay, wool and dried fruit.

Similar to Caltrop, Khaki weed is another prostrate, summer-growing weed that has germinated recently as a result of the high rainfall across the region. Known as an alert weed, Khaki weed is a declared plant that poses a serious threat but is not yet established. Its weed seeds only remain viable in the seed bank for two years, so if you control the plant and conduct follow-up management for two years, you can eradicate it from your property.

Landscape Officers from the Northern and Yorke Landscape Board can help landholders by providing a free weed identification service and advice about the best control methods. Call us on 8841 3400 or email ny.landscapeboard@sa.gov.au

 

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