First Confirmed Case of Glyphosate-Resistant Italian Ryegrass in the UK

In early 2025, a significant development occurred in UK agriculture: the first documented instance of glyphosate resistance in a weed species was confirmed. Researchers from ADAS identified a population of Italian ryegrass (Lolium multiflorum) on a farm in Kent that exhibited resistance to glyphosate at the maximum label rate

What Does This Mean for UK Agriculture?

Glyphosate is a widely used herbicide essential for effective weed control in arable farming. The emergence of resistance in Italian ryegrass poses a potential threat to crop production, as it could lead to increased reliance on alternative herbicides or mechanical weed control methods, both of which can be more costly and less effective 

Factors Contributing to Resistance

The development of glyphosate resistance in Italian ryegrass is believed to be due to genetic mutations that enable the weed to survive herbicide applications. Contributing factors include:

• Repeated Use of Glyphosate: Continuous application of glyphosate without rotation with other herbicides can select for resistant individuals.

• Reduced Tillage Practices: Minimal soil disturbance can favor the survival and spread of resistant weed populations Late Drilling of Crops: Delaying sowing can provide additional time for weed growth, increasing the likelihood of resistance development.

Steps to Mitigate Resistance

To manage and prevent the spread of glyphosate-resistant Italian ryegrass, farmers are advised to:Implement Integrated Weed Management: Combine chemical, cultural, and mechanical control methods to reduce reliance on glyphosate.

• Rotate Herbicides: Use herbicides with different modes of action to prevent the selection of resistant weed populations.

• Monitor Weed Populations: Regularly assess fields for signs of reduced herbicide efficacy and take appropriate action if resistance is suspected

• Adopt Best Practice Guidelines: Follow recommendations from the Weed Resistance Action Group (WRAG) to minimize the risk of resistance development .

Looking Ahead

The confirmation of glyphosate-resistant Italian ryegrass in Kent serves as a wake-up call for the agricultural industry. While this case is currently isolated, the potential for resistance to spread underscores the need for proactive management strategies. Continued research and adherence to best practices will be crucial in preserving the effectiveness of glyphosate and ensuring sustainable weed control in UK agriculture.

For more detailed information and guidance on managing glyphosate resistance, visit the WRAG's official website