United Kingdom
December 22, 2015

Source: AHDB Cereals & Oilseeds

The 2015 AHDB Cereals & Oilseeds Agronomists' Conference included a series of questions to gauge agronomists’ opinions on the potential threat of glyphosate resistance developing in UK weeds.

Most agronomists felt they would not be able to produce cereals and oilseeds cost-effectively if glyphosate was not available and many planned to change their glyphosate strategies to help maintain its efficacy.

Taking place on 8 December, James Clarke, ADAS and the Weed Resistance Action Group (WRAG), led the questioning during his talk entitled: ‘Weed resistance: Should you jump before you get pushed?’

At the heart of the presentation were WRAG’s guidelines, published by AHDB in June, developed in response to the ‘real risks’ of glyphosate resistance developing in UK weed populations.

While WRAG and AHDB emphasise there are currently no known cases of glyphosate resistance in UK weeds, 34 weed species have been reported to have developed resistance to glyphosate globally. 

Watch the video:

Weed resistance: Should you jump before you get pushed?
James Clarke - ADAS and the Weed Resistance Action Group

During the interactive session, Mr Clarke asked three questions:

Question 1

Between harvest and drilling (up to and including autumn 2014) did you use three or more applications of glyphosate (per year)?

Most delegates voted that they did not use three or more applications of glyphosate.

This was considered welcome news as avoiding repeat applications of glyphosate is considered to be a key resistance management measure.

Video: Watch the vote

Question 2

Could you produce cereals and oilseeds cost-effectively if glyphosate was not available?

Most delegates voted that they would not be able to produce cereals and oilseeds cost-effectively if glyphosate was not available. But it was interesting to note that some delegates felt they could farm without glyphosate.

Video: Watch the vote

Question 3

Will you change your strategy to maintain the efficacy of glyphosate?

Encouragingly, most delegates voted that they were planning to change their strategies in response to the new information provided by WRAG and AHDB.

Video: Watch the vote

Learning lessons from the past

Mr Clarke looked back at resistance developments in major weed species in the UK since the 80s.

He said that most developments should have been preventable but, as alternative herbicides were still available, only subtle management changes were implemented.

‘Many modes of action have either been lost or resistance is an issue and the effort is now placed on protecting what is left,’ added Mr Clarke.

In the full presentation, four key resistance management messages were presented:

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 condition

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.

Mr Clarke also informed the audience that AHDB is leading a £500,000 investment in R&D to close knowledge gaps and put growers in a better position to prevent glyphosate resistance developing in UK weed populations.

All conference presentations and videos can be viewed at cereals.ahdb.org.uk/agconf 

Read the guidelines

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

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

Website: http://cereals.ahdb.org.uk/

Published: December 22, 2015