14 August 2019

Improving gamba grass control on Cape York and throughout northern Australia was the topic of discussion at a two-day workshop held in Cairns recently.

Over 40 land managers, scientists and weed control experts from across Cape York and northern Australia attended the workshop to contribute their knowledge to the design of herbicide trials which will take place over the next 18 months.

Gamba grass was planted across northern Australia as a pasture species in the mid-1980s and has spread rapidly. It was declared a Weed of National Significance in 2012, and listed as a key threatening process under the Environmental Protection and Biodiversity Conservation (EPBC) Act. However it continues to spread, increasing fire risks and significantly disrupting biodiversity and ecosystem services.

Management options for gamba grass in natural areas are limited as there are few registered herbicides available, all have off-target effects on native vegetation, and they usually require application during the wet season when plants are actively growing but when access is most difficult across northern Australia.

A key outcome of the workshop was a consensus on the most promising herbicides and application methods to include in the project field trial design with a focus on minimising off-target effects on native vegetation and dry season applications.

The use of fire as a gamba management tool was also a topic of discussion at the workshop. The Fire and Weeds project team presented results from their collaboration with NT Parks, Wildlife and Heritage Division which showed herbicide application and excluding fire can lead to reduced gamba grass cover and increased tree health.

Project leader, CSIRO’s Dr Helen Murphy said the high attendance at the workshop demonstrated the urgent need for more knowledge and new options for effective control of Gamba grass. Sites for the herbicide trials will be established in far north Queensland in the coming months.

Group photo of attendees at gamba workshop

Helen Murphy facilitates knowledge sharing from experts at the gamba workshop

NESP 2.3 project leaders Natalie Rossiter-Rachor and Samantha Setterfield, with Tom Price (NT weeds branch) and Steve Dwyer (NT Parks, Wildlife and Heritage)