Current: Annual broad-leaved weed control in sugar beet

Timescale: March - December 2024
Project Lead: Pam Chambers British Sugar
Project Sponsor: British Sugar and BBRO

Project Summary

The project will look at economic and feasible options for annual broad-leaved weed (ABLW) control in sugar beet in the absence of triflusulfuron-methyl (TSM) on fen and sandy soil types. TSM has not been renewed in Europe and use is currently being sought under Article 4.7 which at best would provide an extra 5 years of use.

Main Objectives

The renewal process has not yet commenced in Great Britain (G.B.) but decisions are likely to be influenced by those taken in Europe. The project will also include treatments with and without phenmedipham (PMP) which is also undergoing the renewal process. Treatments should highlight that growing the beet crop without PMP would be impossible where growing conventional beet and would help support its case for renewal within G.B. Currently around 80% of the G.B. crop is grown using conventional beet and would receive PM P and increasingly SMART beet also receive a 'holding' spray consisting of PMP.There are currently only 11 actives approved for use in the sugar beet crop to control ABLW's and two can only be used on SMART beet. Of the actives approved PMP, metamitron (MTM), ethofumesate (ETO) and triflusulfuron-methyl are the four key components of weed control programmes in sugar beet. ETO is the only active that has recently been renewed in G.B, the rest must go through the renewal process within the next few years.
Manufacturers will carry out weed control trials to promote the actives that they are supporting through the renewal process and will generate useful data. However, the focus will be on programmes that use their own products and will not necessarily be the most economic options for the sugar beet grower.
SMART beet my increase in market share and these rely on the use of thiencarbazone-methyl and foramsulfuron, both acetolactate synthase (ALS) chemistry. There are already known instances of weed resistance to ALS chemistry in G.B and globally weeds are known to become quickly resistant to ALS inhibitors, presumably because these herbicides have a single mode of action, and many have long residual activity. Where resistance to ALS has already developed then the addition of
'conventional chemistry' such as PDM is required to give adequate weed control in SMART beet.

The proposal is to carry out fully replicated trials on two key soil types to demonstrate issues that may occur if TSM and PMP are not renewed in the UK and to look at alternative programmes.
The trials will consist of a maximum of 16 treatments x 4 reps and will have a pre-em followed by 3 post-em timings on the sandland site and a maximum of 4 post emergence applications at the fenland site.

Within Europe beet research organisations have been carrying out trials for several years looking at alternative options, these programmes will be consulted for efficacy. However, sugar beet growers in the UK differ from their European counterparts as a) rates of application tend to be lower b) number of applications tend to be higher c) actives available and label requirements differ d) many key weeds are the same e.g. CH EAL (fat-hen) but there are variations between countries.


Outcomes / Key Message For Growers And Industry

Under review
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