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Look out for serious weed of irrigated areas

The declared weed Praxelis poses a threat to irrigated agriculture. Image supplied by WA Government.

Landholders and residents in the Ord River Irrigation Area (ORIA) are encouraged to be on the lookout for an invasive weed found near Kununurra.

The WA Department of Primary Industries and Regional Development has found Praxelis (Praxelis clematidea) on several small rural landholdings north of town.

Department biosecurity officer Peter Robson said the weed thrived in irrigated areas and posed a risk to tropical crops and rangelands.

“Praxelis invades a range of soil types in the higher rainfall areas of Northern Australia and can become the dominant herb in open woodlands, crops and grasslands, particularly where the wet season rainfall is supplemented by regular watering during the dry season,” Mr Robson said.

“It can significantly add to the cost of managing horticultural crops such as bananas and other fruits.

“There is some evidence that Praxelis can be toxic to both stock and humans if ingested.”

The plants have been removed and the Department will be inspecting nearby properties as part of follow-up surveillance to determine the spread of the pest.

Praxelis is an annual or short-lived perennial herb with most plants growing to between 40cm and 80cm high. It has hairy, very brittle stems with serrated leaves and the flowers are pale purplish-blue. It produces hundreds of small black seeds with tufts that allow it to be spread by the wind. The plant can easily be confused with the ageratum or billy goat weeds.

“The best way to distinguish Praxelis is that, when crushed, its soft leaves emit a powerful odour similar to cat’s urine,” Mr Robson said.

“This weed can be hand pulled if it has not begun to flower. Mature seed can drop off and lead to increased spread, so early identification and action is the best approach. For larger areas, spraying with glyphosate is effective.”

Source: WA Government

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