Brome grass behaviour & management

Sam Kleemann¹, Chris Preston¹ and Gurjeet Gill¹

University of Adelaide, School of Agriculture, Food & Wine¹

Funding: UA00060, UA00149, UCS00020, and UQ00080

Key Words: brome grass, weed management

Key messages

• Brome grass has increased in prevalence across the South Australian and Victorian Mallee since adoption of no-till farming and with intensification of cropping.
• The ecology of brome grass has changed, making it more problematic to control in crops. Higher levels of seed dormancy are allowing brome to thwart early control tactics, resulting in greater emergence in-crop.
• Increased dormancy was associated with a requirement for cold stratification or chilling. Under field conditions this increased chilling requirement would not be met until late autumn or early winter.
• Knockdown herbicides are less effective in the management of highly dormant populations of brome. Therefore, brome grass management has become heavily reliant on Group A and B herbicides, especially the Clearfield™ technology, which is expected to increase the risk of herbicide resistance development.
• Because of high levels of seedbank persistence from one year to the next (~25%) multiyear control of brome grass is required to exhaust seedbanks to more manageable levels. Plan a three-year rotation.

Acknowledgements

We are grateful to GRDC for providing project funding (UA00060, UA00149, UCS00020, and UQ00080).