New BYDV tool to help cereal growers cut insecticide sprays

Cereal growers will soon have access to a new digital tool designed to help manage barley yellow dwarf virus (BYDV) while potentially reducing the number of insecticide sprays needed in winter cereals.

The new model, due to launch this autumn by AHDB, aims to give growers greater control over aphids – the insects responsible for spreading the virus – while improving decision-making around crop protection.

BYDV remains one of the most damaging diseases affecting winter cereals and can cause significant yield losses if virus-carrying aphids infect crops early in the season.

Managing aphids has become more challenging since neonicotinoid seed treatments were withdrawn in 2018, prompting a return to autumn pyrethroid sprays.

Although pyrethroids are relatively inexpensive, every application increases the risk of insecticide resistance and can place pressure on beneficial insects. Researchers say this makes accurate spray timing increasingly important.

The existing BYDV management tool, which has been available for several years, predicts when the second generation of aphids is likely to appear in crops – the stage most closely linked with virus transmission.

It works using just two inputs: a start date, typically crop emergence or a spray date, and accumulated daily air temperatures from that point.

While the system has helped growers time insecticide applications, scientists say it does not account for many factors that influence virus transmission.

As a result, the tool tends to take a cautious approach and can recommend more sprays than may be required to prevent economic yield losses.

New research has created the opportunity for a more advanced system.

Following advances in aphid biology, virus epidemiology and computer modelling, a review of BYDV risk carried out by the Game and Wildlife Conservation Trust identified the potential to develop a more sophisticated management tool.

Based on the review’s findings, ADAS was funded in 2019 to develop a new model capable of incorporating a wider range of risk factors.

Although several aphid species can transmit BYDV, researchers confirmed that the bird cherry–oat aphid is the most significant virus vector across the UK.

Other species, including rose-grain aphid and grain aphid, are seen far less frequently in winter crops during the autumn period.

Monitoring data from the Rothamsted Insect Survey suction-trap network has supported these findings by tracking aphid migration patterns across England and Wales.

The new model combines this monitoring information with weather data and farm-specific details.

These include minimum, maximum and average temperatures, as well as cereal type, sowing date, plant populations, predicted yield, grain price and treatment costs.

Initial validation work found the model accurately predicted BYDV risk when compared with virus symptoms observed in untreated crops.

Researchers say the tool also matched or improved control compared with the existing BYDV system in tramline and plot trials.

Importantly, this was achieved with fewer insecticide applications while delivering yield benefits where BYDV infection occurred.

The system automatically draws on several embedded data sources, including five years of historical weather patterns and temperature forecasts for the coming fortnight.

It also uses data from nearby suction traps to assess aphid migration and virus risk in the surrounding area.

Farmers only need to enter a small number of details, including crop type, plant population, sowing date, predicted yield and grain price, along with their farm location.

Using these inputs, the model calculates daily BYDV infection risk and identifies optimal spray timings where treatment is needed.

It also assesses the likely benefit of follow-up sprays, accounts for the persistence of pyrethroid insecticides and runs cost-benefit analyses for each potential application.

The tool is also designed to support cultural control decisions before drilling.

In higher-risk situations, delaying drilling until after mid-September or choosing varieties with BYDV resistance or tolerance can significantly reduce virus pressure.

ADAS was funded last year to complete development of the model and convert it into a web-based application.

A small group of growers is now helping researchers refine the tool before launch, with two online user-group meetings scheduled for later this month.

Lead crop protection scientist Sacha White said farmers are encouraged to take part in the final stages of development.

“A powerful new BYDV management tool will arrive this autumn to give farmers greater control over aphids in winter cereals – and you can help us develop it,” he said.

The new BYDV management tool is expected to be available to growers ahead of the 2026 autumn drilling season.