Integrated control of Chilean Needle Grass

Summary

Chilean Needle Grass (CNG) is an invasive perennial weed that lowers the productivity of grazing pastures as it is not palatable. It can also cause seed contamination in sheep and lambs, which decreases meat yield and can cause animal health and welfare issues.

Producers initiated this project to better understand control options for managing the long-term problems caused by CNG, by evaluating the effects of different rates and application of herbicides (flupropanate and glyphosate).

Flupropanate led to a 40% decline in the number of CNG plants and glyphosate reduced the number of seeding stems by about 95%. These results provide a solid basis for CNG control strategies, such as quarantine and biosecurity practices, herbicide use and good grazing management.

Objectives

The primary aim of this project was to engage nine producers in the Guyra region of NSW to evaluate and adopt one of three control programs of CNG. The control programs aimed to increase stocking rates and gross margin of sheep enterprises by reducing the amount of CNG in pastures.

Key findings

Good grazing management can increase the density of other, more productive pasture species, which reduces the ability of new CNG plants to establish.

The use of flupropanate led to a 40% decline in the number of CNG plants but also reduced non-target pasture species, which raised concerns about the negative effects it can have on desirable pasture species.

Pasture topping with low rates of glyphosate reduced the number of seeding stems by about 95%, providing an effective option to reduce seed production and spread of CNG.

Benefits to industry

Reducing CNG seed production is an important aspect to control its spread. The management strategies outlined in the project can help improve paddock productivity and reduce economic losses.

MLA action

MLA supports the conclusions made during this project and recommends that producers adopt the management strategies outlined in the final report, such as:

• utilising effective quarantine practices to reduce the spread of CNG onto the farm
• reducing the spread of CNG on properties that already have it, with a focus on reviewing the farm tracks, vehicles, stock movements and paddocks at the edge of any infestation.

Future research

Future research into CNG should focus on methods to improve the palatability of CNG for livestock, as this is a key factor in being able to use the plant for profit rather than treating it as a weed.