Farmers raise concern after UK detects first 'unkillable' weed in Kent, what is glyphosate-resistant weed

For the first time, scientists have identified a glyphosate-resistant weed in Britain with Italian ryegrass in Kent becoming the first known case of resistance to the widely-used herbicide.

Italian ryegrass is an annual grass weed that particularly affects wheat fields. The weed competes fiercely for light, nutrients, moisture and space, making it a persistent challenge for farmers.

Glyphosate was long regarded as one of the most powerful and effective weed killers but has now been rendered ineffective against this aggressive weed, which is growing in multiple fields across the region and known for its ability to control weeds in agricultural settings.

In the UK, it is particularly useful in preparing fields for sowing by eliminating all vegetation. It works by blocking the EPSP synthase enzyme, which is crucial for plant growth.

While glyphosate is designed to target weeds without harming genetically modified crops that are resistant to the chemical, its widespread use has raised concerns in recent years- especially following a 2015 World Health Organization (WHO) declaration that glyphosate is a probable carcinogen.

The emergence of glyphosate-resistant Italian ryegrass in the UK highlights the growing issue of herbicide resistance, which has become a global concern in agricultural science.

Paul Neve, a professor of crop science at the University of Copenhagen, told the Guardian that weeds account for a larger loss in crop yield than both insect pests and diseases.

However, the researcher who discovered the weed, John Cussans, told the Telegraph that it is unlikely to spread rapidly as the resistance is likely arising from natural selection. However, he warned that more cases could emerge and scientists have now ramped up monitoring efforts to track the spread of glyphosate-resistant Italian ryegrass across the UK.

Farmers are already facing a challenging environment, preparing their fields for the 2025 growing season amidst concerns about inheritance taxes and mounting financial pressures. With the increasing frequency of herbicide-resistant weeds, farmers may find themselves forced to adopt more costly, time-consuming methods to control weeds.

The global concern over glyphosate resistance has been growing for years. Globally, glyphosate resistance has been detected in various weed species, with 354 confirmed cases across 57 species worldwide. However, this is the first time the UK has reported glyphosate resistance in the UK.