Web integration of a model for Barley yellow dwarf virus (BYDV) risk assessment in cereals

Aphids can transmit barley/cereal yellow dwarf viruses (BYDV) to cereals.

Pyrethroid insecticides are often used to manage the principal aphid vectors (bird cherry-oat aphid and grain aphid), especially during autumn, which is the main period for virus transmission.

However, an overreliance reliance on pyrethroids is not sustainable.

UK grain aphids are already associated with moderate levels of pyrethroid resistance.

Every spray increases the risk of selecting for stronger or new forms of resistance in aphid vectors.

The industry needs a reliable system to indicate when cultural control approaches should be considered and when a spray is likely to be economically worthwhile to help minimise the overall use of insecticides.

An AHDB project (concluded in 2024), developed a system that models aphid population dynamics, BYDV epidemiology and risk.

The model provides:

1. A cultural control element to assist risk-based decisions ahead of drilling
2. A spray support element to guide spray decisions after drilling

The model considers many variables relevant to BYDV management, such as drill date, aphid pressure, the proportion of aphids carrying virus (viruliferous aphids) and crop economics.

The model outputs showed a very good correlation with BYDV symptoms in surveys of untreated crops.

Using the model to time sprays provided effective control of BYDV in field trials (although BYDV pressures were generally low).

This project will create an application programming interface (API) to facilitate the development of software solutions based on the model.

It will also refine model parameters to improve field accuracy.

For example, the model will be improved to consider weekly data on viruliferous aphids (rather than seasonal averages) and account better for multiple spray recommendations.

It will also consider more economic factors in breakeven spray calculations, such as the no-insecticide payment option in the Sustainable Farming Incentive.

Supply of a BYDV DSS tool

The API developed in the above project will allow the development of software applications based on the BYDV model rules.

To develop a decision support system (DSS) that allows users (e.g. farmers and agronomists) to enter modelling data and calculate results to inform pre-drilling and post-drilling decisions, AHDB has awarded a separate goods and services contract (also to RSK ADAS Limited).

This work will develop a BYDV DSS for public release by September 2026 (in time for key autumn decisions).

The development phase will consider user feedback on mock-ups and drafts.

Most of the project funds (87%) will underpin the development and release of the public DSS, with the remainder used to maintain the DSS until the end of the 2028/29 financial year.

AHDB will continually review the tool, including its impact and scope for improvement, which will inform longer-term investment decisions.

Project date: 5 January 2026 – 31 March 2029

Total project value: £113,377.20 (AHDB contract)

Project leader: RSK ADAS LIMITED

Providing answers to your questions

This research project was funded via a levy-payer-led commissioning process.