Rice Weed Management in Australia (Presented by Malcolm Taylor, Agropraisals Pty. Ltd.)
Overview: This session at the 2024 Rice Extension Pre-season Grower Meetings focused on weed management challenges in Australian rice farming. The discussion highlighted the impacts of different seeding methods on weed populations and evolving strategies for both drill-sown and water-seeded rice systems.
Key Topics:
Seeding Method and Weed Impact:
- Drill-sown rice: Faces predominantly grass weed species like Barnyard grass, Silvertop grass, and Upland broadleaf weeds such as Smartweed.
- Water-seeded rice: Affected more by aquatic weeds like Dirty Dora, Arrowhead, and Starfruit, with grass weeds also appearing in shallow waters.
Challenges and Solutions:
- Glyphosate-resistant ryegrass is a growing issue, and there's a push for the reintroduction of cultivation practices.
- New herbicide combinations like the "4-way mix" (SHARPEN, LONDAX, and SEMPRA) showed promising results in trials, expanding weed control spectrum and residual effect.
- The upcoming herbicide DODHYLEX (tetflupyrolimet) offers new floodwater delivery options with excellent crop safety and effective control of Barnyard and Silvertop grasses in water-seeded rice.
First Principles in Weed Management:
- Prepare fields with even grading, clean seedbeds, and effective drainage to optimise herbicide application.
- Ensuring clean channels and minimising off-target drift is critical.
Herbicide Resistance Management:
- A key focus is using multiple modes of action (MOA) on the same weed species cohort to prevent herbicide resistance.
Key Objectives:
- Achieving weed-free rice crops using reliable and affordable treatments.
- Prioritizing crop safety and sound herbicide resistance management.
Advanced Weed Control Techniques:
- Adoption of DODHYLEX, which delivers outstanding efficacy in floodwater with combinations tailored for specific weed spectrums.
- Developing strategies against smartweed using pre- and post-sowing treatments like HAMMER and SHARPEN.
Takeaways: This session stressed the need for integrated weed management approaches that involve both chemical and cultivation practices to stay ahead of resistance issues and improve overall rice yield.