Research Reports
To Evaluate the Drift from Aerial Applications of Asulox in North Yorkshire (Final Report)
Date: 21 December 2023
Title: To Evaluate the Drift from Aerial Applications of Asulox in North Yorkshire. Final Report.
Author: Jeff Old & Professor Roy Brown
Description: The objective of this study was to provide additional data and evidence for determining effective and safe buffer zone, currently set at 90m, when applying Asulox from the air. The trial was conducted on 16th August 2023 at Lowna on the North York Moors.
Trial A – Aerial Application. Year 2 Report
Date: 21 December 2023
Title: Trial A – Aerial Application. Year 2 Report.
Author: Professor Roy Brown
Description: This report includes the comparison between Asulox, Validate and Squire Ultra applied from the air at standard label rates. Efficacy and the effects on Non-Target Species (NTS) have been the primary focus and includes the first time Squire Ultra has been properly assessed for aerial efficacy. Information on canopy penetration and the pattern of drift distribution has also been incorporated into the study. The trial was undertaken at Lowna in late July 2021 (pre-spray) and a full survey continued into August 2023 (two years after spraying) with the third survey report planned for 2024. Year 1 results are also included.
Trial B – Ground Applied Herbicides at Permitted Label Strength. Year 2 Report
Date: 21 December 2023
Title: Trial B – Ground Applied Herbicides at Permitted Label Strength. Year 2 Report
Author: Professor Roy Brown
Description: These comparative trials were established at the same time as the aerial trials to collect further information on chemical efficacy for ground-based application. Asulox, Squire Ultra and Genoxone were applied and monitored, along with a series of control plots. Approved label strengths were used throughout the study. This is the first field trial of Genoxone as a potential chemical control agent for bracken and began in late July 2021 (pre-spray) and continues to September 2022 (two years spraying). The study was conducted at Lowna, with final monitoring to take place in July/August of 2024. This report included both year 1 and year 2 results.
Trial C – Asulox Plus Adjuvants/ Drift Retardants (Ground Application). Year 2 Report
Date: 21 December 2023
Title: Trial C – Asulox Plus Adjuvants/ Drift Retardants (Ground Application). Year 2 Report
Author: Professor Roy Brown
Description: This set of trials compares the performance of hand applied Asulox alone, compared with five approved adjuvants/drift retardants and Asulox mixes at label rates. Standard untreated plots were included in the random trial blocks. They compare the control efficacy and NTS/ habitat response with Asulox (both on its own and combined with one of five drift retardant/ adjuvant products) applied as standard label concentrations. This report summarises first and second year monitoring from pre-spray (2021) to two years after spraying (2023). 2024 is expected to be the final year of data collection, with a 3-year report due after completion.
Trial D – Canopy Penetration (Ground-based application)
Date: 21 December 2023
Title: Trial D – Canopy Penetration (Ground-based application).
Author: Professor Roy Brown
Description: This trial was undertaken to measure the distribution of spray movement through the canopy to the ground using two different nozzles. Both were standard to ground booms, delivering different volumes in live time. Vegetation monitoring was scheduled over two years to quantify the impact of these two spraying volumes in terms of efficacy and NTS compared to control plots. The primary purpose was to quantify chemical penetration of volume and active ingredient applied at 11l/ha which was an aspect of a previous report found here). The trial began spraying in August 2021 and a final assessment undertaken at the two-year point in August 2023. North York Moors National Park, Lowna, was the base of this study.
Trial E – Comparison of the Efficacy and Habitat Safety of Asulox + Validate, Asulox and Squire Ultra.
Date: 21 December 2023
Title: Trial E – Comparison of the Efficacy and Habitat Safety of Asulox (5.5l/ha) + Validate (200ml/ha), Asulox (11l/ha) and Squire Ultra (60gm/ha).
Author: Professor Roy Brown
Description: Carried out at Lowna, North York Moors National Park, ground-based boom applied Asulox and Squire Ultra (at standard label rates) were compared along with the effects on efficacy and NTS. This report summarises both pre-spray and one-year post spray data. 5.5l/ha Asulox plus 200ml/ha Validate mix comparisons were also made to evaluate the potential to lower the use of asulam active in the future, however with the removal of Asulox from the European Market, this is now purely for academic purposes. Established in late August 2022, it continued on to its completion in August 2023 collecting one-year post spray data.
National Bracken Control Chemical Trials - Dumfries Phase 4, Year 2 Report
Date: 27 April 2023
Title: National Bracken Control Chemical Trials - Dumfries Phase 4, Year 2 Report
Author: Professor Roy Brown (R&D Applied Biology)
Description: The report provides further information on the efficacy and ecological safety of products containing asulam and amidosulfuron when used to control bracken. A comparison between the effects of different application rates applied early and late within the bracken season was undertaken, with year 1 and year 2 results concluding amidosulfuron generally is not a viable treatment for bracken. The results of the first year indicated asulam when applied late in the season and amidosulfuron applied early in the season, could be considered effective primary treatments. And a confirmation in year 2 with further amidosulfuron treatments ineffective after the first year.
ADAS Report: Comparative assessment of risks of two bracken herbicides
Date: 1 December 2022
Title: Comparative assessment of risks to non-target plants and soil invertebrates and soil persistence of two bracken herbicides: asulam and
amidosulfuron
Author: Sarah Cook, Steve Ellis, Susan Kelly, Marie Brown
Description: The report provides a comparative assessment of the two herbicides and indicates the strengths and
weaknesses against a range of higher and lower plants (bryophytes, pteridophytes) and soil
mesofauna. An indication of the strength of the evidence for each species is given, including
susceptibility at specific growth stages. Gaps in knowledge were identified and suggestions made for
further experimental work.
How long do bracken control treatments remain effective?
Date: 3 November 2022
Title: How long do bracken (Pteridium aquilinum (L.) Kuhn) control treatments maintain effectiveness?
Author: Ilgın Akpınar, Josu G Alday
Description: Pteridium aquilinum is a problematic, perennial, invasive species worldwide that poses serious problems in the
British uplands. However, there is a lack of knowledge on long-term success in terms of weed control and land
improvement. We assessed the effects of six P. aquilinum-control treatments at two acid-grassland sites in the
Scottish Borders (Sourhope 1 & 2).
National Bracken Chemical Control Trials
Date: 24 October 2022
Title: NBCCT 2022 Summary Report
Author: Roy Brown
Description: identification of features of amidosulfuron that had not be presented clearly previously including how the uptake of the herbicide by bracken occurs and the implications for control strategies.
Asulam Drift Trials 2022
Date: 24 October 2022
Title:To Evaluate the Drift from Aerial Applications of Asulox in North Yorkshire
Authors: Jeff Old, Roy Brown
Description: two further sets of trials data were collected to confirm the drift pattern from an aerial boom with Pencil Jet nozzles used to apply Asulam to bracken to help in making informed decisions relating to the revision of the required buffer zone against waterbodies. This additional data combined with the 2021 data adds more support to the reduction of the current buffer zone from 90m.
Asulam and Wet Flush Moorland Plants
Date: 16 February 2022
Title: The effect of asulam herbicide on wet flush moorland plant communities on the North York Moors National Park
Authors: Roy Brown, S Holloway
Description: A series of transects were established across sprayed and unsprayed wet flushes to determine the effects, if any, of direct asulam spray and drift on the plant communities. The original report was prepared in 1995, but it has been reviewed to allow it to contribute to the current discussions about the use of Asulam. See the conclusions on p27 of the report, "The effect of asulam on wet flush plant communities was found to be minimal with a significant number of sensitive species including P. aquilinum remaining. Sphagnums and rushes had not been reduced in diversity or density in the sprayed flush ...."
National Bracken Chemical Control Trials - Reprise Reports - Author: Roy Brown
Fawdon Farm 2020 + 2021 Reprise Report - 25 October 2021
Sandscale 2021 Reprise Report - 14 November 2021
Dumfries3 Final Report years 4-5 - 10 December 2021
Challacombe 2019 Final Reprise Report - 10 December 2021
Asulam Drift Trials
Date: 19 September 2021
Title: To Evaluate the Drift from Aerial Application of Asulox
Author: Jeff Old, Roy Brown
Description: further data are provided to evaluate the drift pattern from Pencil Jet nozzles and to allow informed decisions to be made about the required buffer zone against surface water bodies during aerial application of Asulam products for bracken control.
Bracken Canopy Penetration Trials
Date: 15 September 2021
Title: An evaluation of the Penetration of Ground Applied Asulox through a Dense (90% plus cover) Bracken Canopy
Author: Jeff Old, Roy Brown
Description: generic information is provided on the role of the bracken canopy in intercepting spray volume applied at approved rates, using standard back pack spraying equipment.
National Bracken Chemical Control Trials
Date: 29 January 2021
Title: NBCCT 2012-20 Final Summary Report
Author: Roy Brown
National Bracken Chemical Control Trials - Site Dumfries 4
Date: 16 November 2020
Title: Testing alternative Herbicides for Bracken Control - Initial Set-Up Report
Author: Roy Brown
Date: 25 October 2021
Title: Testing alternative Herbicides for Bracken Control - Interim Report (Year 1)
Author: Roy Brown