Yellow bristle grass (Setaria pumila) appears to have significantly increased its range across parts of Taranaki.
In recent times, infestations have been identified at Urenui, Tikorangi, Motonui, Lepperton, Inglewood, Okato and Manutahi.
Yellow bristle grass is an annual summer grass which is invading pastures from roadside infestations, via stock movement and in infested hay, balage and silage.
Download the "Ute Guide" (see box at right) for advice on controlling yellow bristle grass.
Like many weeds, yellow bristle grass will readily colonise bare ground — for example, areas that have recently been sprayed.
Droughts, which result in pastures opening up, also exacerbate its spread. However, poor weed hygiene practices are also a factor. |
This easy-to-read guide covers identification and control methods. (© MAF)
Yellow Bristle Grass - The Ute Guide (1.7 MB) |
Seeds may be spread from affected properties to "clean" properties via seasonally grazed stock, outsourced feed supplements (hay and balage), roadside grazing, agricultural contracting machinery, road reserve mowers, road works machinery and other vehicles.
Once established, it is a prolific seeder and becomes dominant in a paddock within a few years.
While yellow bristle grass is palatable to livestock during the vegetative stage, it has poor nutritive values and stock avoid it after seed heads emerge (mid January to May).
Stock health issues are also of concern as there is evidence that seed heads can cause lesions and ulcers to the mouths of grazing cattle.
On highly productive dairy farms, where yellow bristle grass is prolific, annual feed production may be reduced by up to 20% resulting in increased on-farm costs associated because of the need for supplementary feed and/or pasture renovation. The result is estimated to be about $1,100/ha in lost production.
Yellow bristle grass is likely to have been present in Taranaki for decades. The first reports of yellow bristle grass in Taranaki are dated as early as 1932 at New Plymouth.
Yellow bristle grass is not a declared pest in this region but in response to increasing concern, the Taranaki Regional Council is promoting awareness and encouraging management practices to minimise its spread.
The Council is also monitoring the presence of yellow bristle grass in Taranaki.