Project snapshot: Herbicide resistance in lucerne seed production systems in the southeast of South Australia

  • 6 pages

  • Published: 5 Mar 2024

  • Author(s): Peter Boutsalis, Katrina Copping

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This study evaluated the level of resistance to commonly used herbicide groups in three key weeds affecting lucerne seed crops in commercial production areas of Australia’s primary lucerne seed-growing area.

We report extensive data from 105 paddocks on the frequency and type of resistance in annual ryegrass (Lolium rigidum), barley grass (Hordeum spp.) and sowthistle (Sonchus oleraceus). We found that every annual ryegrass sample tested exhibited herbicide resistance, with the incidence of resistance and cross-resistance lower in both barley grass and sowthistle.

Our research has delivered to lucerne seed growers and advisors industry-specific knowledge that can inform the development of integrated weed management (IWM) strategies for lucerne seed production systems. This information will help the industry take a longer-term seedbank and resistance risk view by considering how they should use the limited herbicide options available, as well as considering the value of introducing new weed management practices to optimise weed control. Ongoing testing, development of new strategies and continued education will be needed to adapt to the ever-evolving challenge of resistance.

For more information on weed management in lucerne, visit the Lucerne Australia website.