Barley disease management research yielding results


Description of impact

SRUC research, which has defined the optimal timing and chemical composition of fungicides and examined pathogen resistance to fungicide, is said tobenefit the UK and Irish barley industries by minimising yield lossesof up to £113,609,000 and €16,220,235 per year, respectively.

Barley is the most widely grown crop in Scotland and the Republic of Ireland, and the second most important in the UK. Diseases of barley crops are managed through annual application of fungicides to kill parasitic fungi and their spores. But incorrect timing of its application or using less effective products, can adversely affect yield and is a major contributor to pathogens [bacterium, virus, or other microorganism that can cause disease] developing resistance to fungicides.

Defining optimal timing and selection of fungicides

In 2001, SRUC in collaboration with the Agricultural Development and Advisory Service (ADAS) and the University of Nottingham, began to investigate the limitations on the yield of UK-grown winter barley crops.
Subsequent research, in collaboration with Teagasc, suggested that fungicides should be applied early in the life of barley crops first to maximise grain number formation prior to flowering, and then to protect the canopy during grain filling. This research showed that, unlike wheat, winter barley yield is sink-limited, i.e. limited by the number and capacity of grains to store dry matter, rather than the supply of assimilates for grain filling.

Further projects funded by the UK and Scottish governments established the optimum timing and chemical composition of fungicides to maximise yield. This work showed that the canopy does not need to be protected for the entire duration of grain filling, and that early applications of certain fungicides can increase grain numbers and yield even when there is little or no disease present. This response appears to be the result of direct physiological effects of the fungicides that occur before flowering. This research further highlighted the importance of early application of fungicides to maximise yield. 
Annual assessments of fungicide performance
The efficacy of fungicide products varies greatly, primarily due to the evolution of fungicide resistance in key pathogens. SRUC research has characterised how resistance to the chemicals in fungicides develops in key pathogens including Ramularia collo-cygni, the agent responsible for Ramularia leaf spot disease of barley.

SRUC researchers worked together with ADAS, the National Institute of Agricultural Botany (NIAB) and Teagasc, to conduct annual field assessments of fungicide performance. The Fungicide Activity Rating website, also run by AHDB, is updated based on these results and constitutes the main avenue for publicising those findings.

Impact on farmer practice
Farmers learn of the insights from our research through three key routes:
1. Since 2006, SRUC research has formed the basis of the definitive national farming advice in the UK through the two
AHDB Guides (Barley Growth and Barley Disease Management), with latest editions published in 2018 and 2016, respectively. It also shaped the advice offered to Irish farmers through the Teagasc Spring Barley Guide, published
in 2015.
2. A programme for UK-wide dissemination, run by the Fungicide Resistance Action Group (FRAG-UK) and hosted by AHDB, also shares a suite of guidelines,
underpinned by SRUC research.
3. The Scottish Quality Crops (SQC) scheme encompasses more than 95% of the cereal acreage in Scotland. In July 2018, SQC established an online pest management planning tool that prompts users towards diverse ranges of
fungicides and balanced mixtures. Completion of this tool is required for farmers to market grain as quality assured. Some 2,228 farmers across Scotland had used the tool by the end of 2020.
Economic Impact
In the UK, the economic impact of our work is derived chiefly from the optimal selection of fungicide product, while in Ireland it arises predominantly from optimal timing of fungicide application.
Use of optimal fungicide programmes results in improvements to barley yields that have been assessed to be worth up to an additional £113,609,000 and €18,300,000 annually to the UK and Irish barley industries, respectively.
This is an edited version of an impact case study, which formed part of a joint submission with the University of Edinburgh to REF2021.