Recent data suggests higher proportions of aphid populations are carrying BYDV

Monitoring aphid migration and virus incidence

The UK Aphid Monitoring Network, delivered by Rothamsted Research and supported by AHDB, tracks aphid migration and virus incidence throughout the autumn.

Each year, more than 1,000 aphids collected from a network of suction traps are tested for BYDV to build a picture of potential virus pressure across the country.

Bird cherry-oat aphids account for most of the samples collected, as they fly in far greater numbers during autumn than grain aphids.

Virus incidence above the recent average

Data collected between 2020 and 2024 showed that, on average, 22.3% of aphids tested positive for BYDV.

This informed the default virus-incidence value used in our BYDV management tool, which currently assumes 21 to 27% of aphids carry the virus, depending on location.

However, recent monitoring results suggest virus incidence may be running above this historic average. In autumn 2025, 34% of tested aphids carried BYDV, while analysis of samples processed so far in autumn 2026 indicates 35% are carrying the virus.

Further samples are still being tested this autumn, and monitoring will continue while conditions remain suitable for aphid flight activity.

Monitoring risk, not just aphid numbers

Sacha White, Lead Crop Protection Scientist, at AHDB, said:

"The majority of aphids still do not carry BYDV, but the latest results suggest a higher proportion are testing positive for the virus than we've typically seen in recent years.

"Monitoring this trend is important because virus incidence is one of several factors that influence the potential risk to crops. As more data becomes available through the autumn, we'll continue to assess what the results are telling us.

"Rather than making decisions based on a single risk factor, following an integrated pest management (IPM) approach growers should consider virus incidence alongside drilling date, local aphid activity, crop value and treatment costs.

"The new BYDV management tool brings these factors together to help growers assess whether an insecticide application is likely to provide a return on investment.

"The tool is updated with regional virus-incidence data from the monitoring network as it becomes available, helping growers make more informed, evidence-based decisions throughout the season."

Using the BYDV management tool

Our BYDV management tool estimates the likely economic benefit of an insecticide treatment by combining information on aphid pressure, virus incidence, crop value and establishment timing.

During the autumn, the tool's default virus-incidence value is replaced with regional data from the UK Aphid Monitoring Network as new results become available.