Prickly pest spreads like wildfire

News release
30 November 2018

Following unusual seasonal conditions, a spiny weed is in danger of becoming a thorny environmental problem, with local landholders asked to help bring it under control.

Late spring rains have resulted in the massive germination of caltrop, a major agricultural pest, across the Adelaide and Mount Lofty Ranges (AMLR) region.

Natural Resources AMLR District Officer David Hughes said the bare ground left behind by the dry winter and spring, and the absence of competing plants, had provided ideal conditions for the germination of the prickly pest.

“If not controlled quickly before Christmas, these weeds will go to seed and could pose a major threat to horticulture and viticulture industries,” he said.

“Often over the Christmas period, farmers and open space recreation managers are on holidays so this plant will thrive and spread unchecked.”

Caltrop is a low-growing prostrate plant with fern-like leaves, yellow flowers and smooth or hairy stems. The one-centimetre woody burrs are studded with sharp spines which get stuck in the feet of stock and wildlife, and contaminate produce such as dried fruit and wool. The plant is toxic to stock and can cause nitrate poisoning, photosensitisation and staggers.

Caltrop also causes havoc in recreational sites such as parks, where the burrs penetrate through thongs and sandals and puncture bicycle tires.

“It is very important to keep caltrop off clean properties and to recognise and destroy plants before they become established,” Mr Hughes said.

Landholders can help stop the spread of caltrop by managing according to seasonal conditions, inspecting areas for new weeds germinating after summer rains; ensuring stock and produce in infested paddocks are cleaned out or shorn prior to transport or sale; creating and maintaining buffer zones; and following farm hygiene practices.

”As a declared pest plant under the Natural Resources Management Act 2004 (NRM Act), caltrop must be controlled by landholders,” Mr Hughes said.

For assistance and advice from a district officer, please phone Natural Resources AMLR on 8115 4600.

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Natural Resources Adelaide and Mount Lofty Ranges