BYDV tool returns to guide cereal spray decisions

Friday, 6 September 2019

People can time pyrethroid sprays on cereals more accurately this autumn, thanks to AHDB’s updated BYDV management tool.

First released in 2018, the tool uses air temperatures, from a network of weather stations, to predict when the critical second generation aphid offspring is likely to spread through cereal crops.

For the first time, the tool uses both observed and forecast weather data to provide an early indication of the optimum time to spray.

About the BYDV management tool

The second aphid generation moves throughout the crop and can spread barley/cereal yellow dwarf viruses (BYDV). Consequently, control of this generation is a key component of a BYDV management strategy.

With seed treatment options no longer authorised for use, a foliar insecticide is the only chemical control option available and spray timing is critical.

The second generation is likely to be present when the accumulated daily air temperatures, above a baseline temperature of 3ºC, reaches the T-Sum threshold of 170. When the threshold is reached, crops should be monitored and a spray considered.

T-Sum calculations should start either:

  • On the day of crop emergence
  • Following a pyrethroid application (account for product persistence, see label)

Based on observed and forecast weather data, the BYDV management tool calculates the T-Sum daily for a range of UK sites.

Access the tool and aphid management information, via