Farmers are being asked to do their bit to help a range of agencies reduce the spread of yellow bristle grass.
It hasn't been declared a pest plant but a big infestation on a dairy farm can drop productivity by 20 per cent, or $1100 per hectare, and force farmers to buy supplementary feed or renew pasture.
The grass seeds prolifically, spreads quickly and is hard to eradicate. There is also evidence that its seeds can ulcerate the mouths of cattle.
It originated in sub-tropical China and has now spread to many parts of the world, including New Zealand. In Taranaki there are outbreaks at Okato, Inglewood and Manutahi, according to Taranaki Regional Council environment services manager Steve Ellis.
It's also elsewhere in the North and South islands and would be well suited to the climates and soils of Wanganui and Rangitikei. Once established it's capable of dominating pasture within a few years.
Yellow bristle grass (YBG) is an annual that grows only in summer. It's palatable to stock at first, but of low food value. By January, when its leaves dry out and seedheads form, stock will avoid it.
It readily colonises bare ground and seeds quickly and prolifically. The seeds are killed in balage and well-fermented silage but they persist and will germinate in effluent and dung.
The grass is being spread by the movement of stock and equipment, and also "jumping the fence" from roadsides into pasture.
Taranaki Regional Council, the New Plymouth, Stratford and South Taranaki district councils, the New Zealand Transport Agency, Federated Farmers and Dairy NZ all want to stop it spreading, and farmers have the most to lose.
One of the most important preventive measures is keeping soil covered with vegetation, mainly by not over-grazing, which may mean farmers reducing their stocking rates. Taranaki Regional Council plans to keep landowners informed. It has lots more information online at www.trc.govt.nz, including tips on eradication.
Those who spot YBG should phone 0800 736222 or email biosecurity@trc.govt.nz