Chilean Needle Grass more than a threat to Agriculture

(Published on 6th July 2017)

NZ Landcare Trust has been working with the Chilean Needle Grass (CNG) Action Group and Marlborough District Council to increase awareness of this significant pest plant. CNG has traditionally been viewed as an agricultural pest plant but recent findings reveal it has the potential to cause significant problems beyond the farm gate.

A discovery several years ago of Chilean Needle Grass (CNG) on the Witherhills Farm Park (a recreational area near Blenheim) has recently been followed by another find near the Omaka Air Field, in an area used for parking at the popular Easter Air Show. This latest development highlights how the pest plant can have a negative impact beyond agriculture and has the potential to affect recreation, tourism and native biodiversity.

This knowledge provided the incentive for a good turn out at an event held at Philip and Virginia Pratts, Blind River farm. Landowners and contractors were there to learn about the importance of defensive actions designed to stop the spread of CNG by animals, machinery and humans.

Simon Harvey who farms in the Medway Valley told landowners he does not want CNG on his property. “Not getting CNG on farm is the best option. The costs associated with animal welfare and reduced production can erode farm profitability, and the situation will get worse if it’s allowed to get into our hill and highcountry.”

In another development, CNG Action Group Chair, Warwick Lissaman, announced the formation of a National Steering Group whose role will be to provide national direction for the control and reduction of CNG. The group will have farmer and Regional Council representatives from Marlborough, Canterbury and Hawkes Bay.

On a field trip to Agresearch trials at Atacama, spray contractor Ben Minehan of Weed Solutions said, “CNG is not like other weeds, the seeds present problems at three different levels."  In addition to the seeds that appear at the tip of the flowering stems, hidden seeds can be produced in nodes along the stem and at its base.

"The aerial panicle seeds and stem seeds can cross pollinate, with the seeds becoming viable from mid December. This is why Needle Grass spreads so quickly." Ben added.

Ben went on to provide an example of a vineyard, suggesting that even when its mowed the plants are still seeding and viable. He stated that the seeds remain viable in the ground for long periods - if it remains dry.  "Over all if needle grass is hammered for 3 years it knocks it back hugely and brings land into production." Ben concluded.

The field trip also visited Tim Struthers, Casey’s Rd property to hear how Tim transformed heavily infested land back into production. He provided valuable information about what sprays he used, when it was applied, summer fallowing and what grass species worked for him. 



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