For the first time in the UK, weeds resistant to the widely-used herbicide glyphosate have been identified. The species responsible for this notable finding is Italian ryegrass, prevalent across the UK, with resistant specimens discovered at a single farm in Kent.
Glyphosate has played a pivotal role in promoting environmentally sustainable farming practices, particularly regenerative agriculture. Weed management experts confirmed the resistance of these plants through thorough greenhouse testing.
“This development could significantly hinder our agricultural transition,” a weed management expert stated. “Herbicide resistance presents a considerable challenge for farmers.”
In the UK, glyphosate is primarily used to eliminate all vegetation before planting, allowing farmers to avoid ploughing which harms soil health, heightens erosion, and diminishes carbon storage. Reducing soil disturbance, along with implementing crop rotation and maintaining ground cover, is fundamental to regenerative agriculture.
“Compared to other agrochemicals, glyphosate is relatively environmentally safe,” noted a research expert. “It has low toxicity and shows minimal bioaccumulation. Moreover, it supports regenerative practices like minimum tillage, which benefits soil health.”
Weeds pose significant challenges for farmers, leading to greater crop yield losses than insect pests and pathogens. Globally, at least 56 weed species, including Italian ryegrass, have developed resistance to glyphosate, a phenomenon that has occurred independently in diverse locations. This issue particularly affects farmers in regions like the US and Argentina, where glyphosate-resistant crops have been extensively cultivated.
Despite these concerns, experts believe that glyphosate resistance has not escalated into a widespread crisis, although it remains a pressing issue on farms where resistant weeds are present. Preventive measures, such as cleaning farming equipment to eliminate seed spread, can mitigate this problem.
Farmers are advised to implement a diverse range of weed control strategies rather than relying exclusively on glyphosate. Research indicates that by focusing on holistic weed management, farmers can potentially see profit recovery within five to ten years.
In 2018, surveillance efforts intensified across the UK, leading to the testing of over 300 Italian ryegrass samples. Experts believe that the resistant species at the Kent farm likely evolved locally, rather than being introduced from other regions. Furthermore, the slower evolution of such resistance in the UK compared to other countries might be attributed to the absence of genetically modified or conventionally bred crops resistant to glyphosate, which allows for more frequent herbicide application.
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