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Guidelines issued in response to glyphosate weed resistance risks

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Guidelines from WRAG (Weed Resistance Action Group) have been published by AHDB in response to the 'real risks' of glyphosate resistance developing in UK weeds.

While WRAG and AHDB emphasise there are currently no known cases of glyphosate resistance in UK weeds, the guidelines build on global experience to help growers maintain the effectiveness of glyphosate as a weed control option.

Guidelines issued in response to glyphosate weed resistance risks

Glyphosate has been around for 40 years and has become one of the most frequently used herbicides across UK crop production.

Increasing resistance to selective herbicides – especially in grassweeds within UK arable cropping systems – and a reduction in available chemistry means the pressure to use glyphosate as a stale seedbed management tool, in particular, is increasing and it is vital to retain its effectiveness.

Without the use of glyphosate, a potential loss of yield and quality would occur across all cropping systems. In particular, it has been estimated that a 20% yield loss would occur without the use of glyphosate pre-drilling.

James Clarke, WRAG Chair and Science and Business Development Manager at ADAS, said: “Globally, 31 weed species have been reported to have developed resistance to glyphosate, so WRAG drafted the guidelines to help agronomists and growers maintain UK efficacy.

“A number of high-risk practices are being increasingly deployed on UK farms which could drive the evolution of glyphosate resistance in UK weeds – including multiple glyphosate applications, sublethal doses and suboptimal application timing – and we wanted to be proactive in highlighting the risks and promoting best practice.

“We have pulled together the latest information, including lessons from global experience, to present key points to ensure the efficacy of this important active in weed control is maintained.”

The new Minimising the risk of glyphosate resistance guidelines include four simple and key messages, supported by more detailed evidence and guidance.

Minimising the risk of glyphosate resistance: key messages

  1. Prevent survivors: Avoid repeat applications to surviving plants

  2. Maximise efficacy: Apply the right dose rate (reduced rates increase the risk of reduced efficacy), at the right timing, in the right conditions

  3. Use alternatives: Use non-chemical options (such as cultivation), where practical, and use other herbicides in sequence

  4. Monitor success: Remove survivors and report potential resistance issues to your advisor and/or the product manufacturer.

Peter Kendall, AHDB Chair, said:  “Our current battle with black-grass resistance is a powerful reminder of why the industry needs to take action before resistance establishes and spreads.

“This new guide will help us all work together to understand and manage the threat of glyphosate-resistant weeds and the associated economic consequences.”

Producing the guidelines also identified several knowledge gaps. AHDB is working with others to explore how these gaps can be addressed to ensure the industry stands the best possible chance of minimising the risk of glyphosate resistance developing in the UK.

A two-page summary of the guidelines (AHDB Information Sheet 03) is available from the AHDB website –


The first opportunity to pick up hard copies of the publication will be on the AHDB Cereals and Oilseeds stand (No 902) at the Cereals 2015 event taking place on 10–11 June at Boothby Graffoe.


A full version of the guidelines is available to download from the WRAG website –


For more information contact

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