Pests

Giant rat’s tail

The Problem

Like other weedy sporobolus grasses, Giant rats tail grass is an aggressive competitor that can reduce pasture productivity and significantly degrade natural areas. Flowering plants are long-lived and can exist for more than 4 years. Their foliage has low palatability for animals when mature and is therefore not selectively grazed. GRT is resistant to fire, slashing, grazing and high competition. However, it is sensitive to some herbicides.

Weedy sporobolus grasses are aggressive, have low palatability when mature, and are difficult to control. They can quickly dominate a pasture, especially following overgrazing or soil disturbance. Giant rat’s tail grass (GRT) poses a significant threat to the productivity of pastures in the Mackay Whitsunday Isaac region. GRT is one of the weedy sporobolus grasses (WSG) with the ability to significantly decrease grazier’s economic viability and degradation of natural areas. Cattle grazing GRT pasture take up to 12 months longer to reach equivalent weight. In 2007 the estimated cost of GRT and other WSG to the pastoral industry was $60 million per year (Bray and Officer 2007).
Attempts to control this weed using conventional methods have often failed and, in some cases, intensified the infestation. Pastures dominated by GRT are common, due to the long-term viability of GRT seed in the soil and the tendency of stock to graze other more palatable pasture before GRT.

Project Description

The project aims to support efforts to eradicate GRT grass, a weed impacting significantly on high quality agricultural land and environmental assets within the Mackay Whitsunday Isaac region.

A variety of control approaches have been utilised over the last 20 years, including enhancing farm biosecurity to monitor and eliminate origin pathways, burning, spraying liquid herbicides, wick wiping, cultivation and fodder crops, over sowing with vigorous perennial grasses and spelling pasture. No single treatment has proven to be the best management practice for reducing the impact of GRT on pastures.

The most common treatment of Giant rats tail grass (GRT) to date has been the use of the liquid or granular herbicide, sodium 2,2,3,3- tetrafluoropropanate, TASKFORCE®. Various results have been recorded for TASKFORCE® applied to GRT infestations across the Mackay Whitsunday Isaac Region. More work is being done to investigate the most effective way of applying this chemical under our regional conditions.

The Reef Catchments Bradshaw GRT Case Study, a project partnered with Pioneer Catchment Landcare and Farmacist.

References
Bray, S. and Officer, D., 2007, Weedy Sporobolus grasses Best Practice Manual, Department of Primary Industries and Fisheries, Brisbane

Further Information
Department of Agriculture and Fisheries Fact Sheet