Chemical Control
Current UK Policy favours the use of non-chemical treatment so wherever possible, physical control is the primarily recommendation. There are a few instances where physical control of bracken may be more challenging such as on steep hills and certain terrain. Lack of time, money and suitable volunteers for control may be amongst other challenges.
Previously, Asulam (the active ingredient in the product Asulox) was used but it is no longer approved for use in the UK or in Europe. Further research is being sought for to look into alternative methods for chemical control and some of this research can be found in briefings below.
Chemical Control Studies & Updates
The Bracken Control Group has previously published briefings exploring other chemical herbicides, the latest update can be viewed below.
Drones
Drones are an intriguing topic when it comes to their incorporation into environmental management. An experimental approval (Extrapolated Trial Permit) for the application of glyphosate from a drone may be approved during the first half of 2024.
A briefing discussion drones and their potential use in bracken control can be found below:
Alternative Herbicides
The loss of Asulox is recognised as a major blow for those who wish to control bracken, and this brings into focus the search for an alternative to Asulox.
This process started in 2012, with the establishment of the National Bracken Chemical Control Trials (NBCCT). Reports on these trials are included under the Research menu of the website and key findings have been summarised in Bracken Briefings 13 & 26.
There is no alternative chemical control option available immediately, and this leaves areas of the country, where physical control methods (such as: cutting, bruising, rolling, ploughing) are not suitable or safe, without a valid bracken control method.
Alternative Herbicides - Glyphosate
Glyphosate (marketed as RoundUp®) is a non-selective, organophosphate pesticide, which is used widely to protect crops against weeds.
Its high solubility in solvents, especially water, and high mobility, allows the rapid leaching of the glyphosate into the soil leading to contamination of groundwater and accumulation in plant tissues.
Glyphosate was included in the NBCCT. It had the lowest level of control on both fronds and rhizome systems, and had the greatest and longest negative impact on the ‘non-target’ habitat attributes. See the National Bracken Chemical Control Trials 2012 – 2020 Final Summary Report - available in Research Reports under the Research menu.
For England, the Rural Payments Agency issued guidance on 9th April 2024 stating that Glyphosate may be used to satisfy the requirements of a Countryside Stewardship (CS) agreement, as an alternative to Asulox, if such use is approved by Natural England or the Forestry Commission.
In view of the potential for long-term damage to soil and non-target species, it remains to be seen whether Natural England or the Forestry Commission will authorise the use of glyphosate for bracken control as part of CS.
Glyphosate may have a role for carefully planned, small-scale control of bracken, but the side effects must be considered before application takes place.
Bracken Control Using RoundUp® Products. Bayer, the owners of RoundUp®, issued a Technical Bulletin in 2022 covering the use of the product for bracken control. The views expressed are Bayer's own and are not necessarily endorsed by the Bracken control Group.
Alternative Herbicides - Amidosulfuron
Amidosulfuron (marketed as Squire Ultra, amongst other products) was introduced around 1992 for the control of broad-leaved weeds in cereals, linseed and grassland.
Amidosulfuron was also included in the NBCCT.
If applied at the same time of year as Asulox, (July-August) outside the bird breeding season, there are questions about the effectiveness of amidosulfuron for controlling bracken.
If applied early in the season (May-June), amidosulfuron has the potential to achieve moderate or good level of control over a three-year period but with a significant negative impacts on both the diversity and structure of the habitat involved.
For more information see Bracken Briefings Nos.14 & 15 and the ADAS Report: Comparative assessment of risks of two bracken herbicides - available on the Research Reports page.
Bayer, the manufacturers of Squire Ultra, has announced that it will not be producing the product after the end of 2024. Therefore, it will not be possible to complete a bracken control programme starting in 2024 that uses Squire Ultra.
In view of the concerns about the side effects, the questions about its efficacy and the lack of long term availability, the use of amidosulfuron products to control bracken is not recommended.