Demonstrating ryegrass control strategies

WHY THIS PROJECT IS NEEDED

A local GRDC National Grower Network industry meeting identified the management of ryegrass as a priority issue for northeast Victoria.  

Cereals form a key part of the rotation for growers in the region, with anecdotal reports of increased ryegrass numbers in this phase due to limited control options. The situation has been exacerbated by poor trafficability in wet and waterlogged paddocks over recent years and excessively wet conditions have also impacted on pre-emergent weed control for some product uses. Consequently, there is interest in exploring management strategies in other phases of the rotation, to drive down ryegrass numbers.

In short: This project is evaluating diverse ryegrass management strategies, with the aim of enhancing crop yield and combating herbicide resistance.

Another consideration is changes in dormancy of annual ryegrass, leading to staggered germination. This is likely a response of local ryegrass populations adapting to control measures and timings. Significant crop yield losses due to the competitive nature of annual ryegrass and the high input costs required to manage this and prevent ongoing seed set, make this an economically significant issue for local growers.  

Project focus

Riverine Plains has established a demonstration trial at Wahgunyah to demonstrate the effectiveness of integrated weed management strategies for control of annual ryegrass. The trial is assessing various ryegrass control strategies over the 2023–2024 growing seasons and will evaluate chemical and cultural management techniques on ryegrass numbers.

Ryegrass populations will be assessed for each treatment at early, mid and late stages of crop development and crop yield will also be measured.

Project outcomes

Various extension and communication activities are helping to increase the understanding of the different management strategies available for annual ryegrass populations and herbicide resistance across the region.  

Results from the project's 2023 trials were published in Research for the Riverine Plains, 2024.

Key messages were:

• Integrating a range of locally validated weed management strategies is important when tackling annual ryegrass.
• Rotating crop types and chemistry are vital components of all weed and disease control strategies.
• It is important to also consider non- chemical weed control strategies, due to the increasing rates of herbicide resistance being seen in local ryegrass populations.
• Seed testing indicated ryegrass resistance to Group 1 herbicides at the trial site.

Further reading

• Preventing herbicide resistance from reducing your grain yields