Gamba grass was planted across northern Australia as a pasture species in the mid-1980s and has spread rapidly. In north Queensland, gamba infestations are found near Bamaga, Coen, Weipa, Cooktown and Mareeba. The grass is also widespread along Cape York roadsides and in isolated patches in the Gulf region. Despite being declared as a Weed of National Significance in 2012, and listed as a key threatening process under the Environmental Protection and Biodiversity Conservation Act, it continues to spread, increasing fire risks and significantly disrupting biodiversity and ecosystem services. Environmental, social and economic costs will increase unless control is improved.
The lack of herbicides registered for use in natural areas is a major barrier to managing gamba grass and other high biomass grassy weed species in the north, especially where infestations cover large areas. Few selective herbicides are available with on-label registration for use in these non-crop areas and therefore current control relies heavily on ‘minor use’ permits. Non-selective herbicides such as glyphosate have off-target effects on native vegetation so are inappropriate for use in natural areas at large scales.
This project is reviewing herbicide and integrated management approaches to controlling gamba and trial various control methods in natural ecosystems to inform best practice and herbicide registration processes. The trials are assessing off-target herbicide effects and recovery following treatment and biomass removal. The project is developing best-practice management guidelines to control gamba incursions and infestations in natural areas, including control methods for selective herbicide application. The guidelines are assisting land managers to better manage gamba, and project outcomes are relevant to the entire gamba grass range across the NT, WA and Qld.
This project is:
This project is led by Dr Helen Murphy from CSIRO, with field monitoring by CSIRO’s Matt Bradford and Andrew Ford. Dr Murphy is being assisted by Queensland Government staff as well as researchers from Charles Darwin University and The University of Western Australia.
Helen Murphy, CSIRO
E: he[email protected]