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.
Encouragingly, most delegates voted that they were planning to change their strategies in response to the new information provided by WRAG and AHDB.
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
For full information and links see: http://cereals.ahdb.org.uk/research/agronomists-conference-2015.aspx or http://cereals.ahdb.org.uk/press/2015/december/22/strategies-to-protect-glyphosate-efficacy-adopted-by-agronomists.aspx