Growers are being urged to act now to protect glyphosate’s future, as a stark warning has been issued following the country’s first confirmed case of resistance in Italian ryegrass.
With pre-harvest glyphosate applications approaching, the Agricultural Industries Confederation (AIC) is calling on growers to strictly follow the Weed Resistance Action Group (WRAG) guidelines.
In January 2025, WRAG confirmed that a single field population of Italian ryegrass had developed resistance to glyphosate at the maximum permitted dose.
This is the first fully documented instance of glyphosate resistance in the UK and has raised significant concern across the agricultural sector.
Three further suspected cases were identified at the time. Subsequent testing revealed that two of these populations showed significantly reduced control from appropriate glyphosate rates, while the third displayed decreased sensitivity.
Throughout spring, additional samples of Italian ryegrass that had survived glyphosate applications were submitted to ADAS for resistance testing.
Preliminary results indicate that several of these populations may also be problematic, though full confirmation is still pending.
The AIC has warned that the risk of glyphosate resistance is being made worse by a significant reduction in mechanical weeding. This includes a move away from traditional cultivation practices that physically disrupt weed growth.
In addition, the increasing adoption of low-disturbance or no-till farming systems, combined with extended periods where fields lie uncropped—such as during fallow or stubble phases without any active weed control—is further contributing to the problem.
With these factors contributing to the mounting pressure on glyphosate efficacy, the body is urging growers to follow the WRAG stewardship guidelines, which include:
• Prevent survivors – avoid repeat applications to any surviving weeds.
• Maximise efficacy – apply the full recommended dose when weeds are actively growing and conditions are favourable. Avoid application during stem extension or in plants stressed by drought, waterlogging, or low temperatures.
• Use alternatives – where feasible, integrate non-chemical methods such as cultivation, and alternate with other herbicide modes of action.
• Monitor success – remove any survivors and report suspected resistance to your agronomist or the product manufacturer.
