Winter barley planting remains a viable option in Northern Ireland, particularly in regions like County Down where growers achieve high establishment rates, according to crops specialist Leigh McClean from the College of Agriculture, Food and Rural Enterprise (CAFRE). Favorable soil conditions over recent weeks allowed farmers to progress effectively with winter cereal sowing before cooler weather arrived.
Warm weather increases Barley Yellow Dwarf Virus risk
Average daily temperatures leading up to the recent cold snap remained significantly higher than typical seasonal expectations for late September and early October. While early sowing and settled weather boost the likelihood of successful crop establishment, they simultaneously elevate the threat of Barley Yellow Dwarf Virus (BYDV) in cereal crops, as confirmed by McClean.
The yield-robbing virus spreads when migrating, infected aphids feed on newly emerged seedlings. These insects can arrive as non-winged pests moving inward from old crop residues and field margins, or as winged travelers capable of covering greater distances.
AFBI tracks aphid populations with suction traps
To track winged aphid populations, the Agri-Food and Biosciences Institute (AFBI) collects weekly samples using a suction trap located at Crossnacreevy and publishes the results online. Daniel Leybourne, AFBI principal scientific officer, stated that aphid monitoring provides growers with an indication of insect numbers compared to previous weeks, the prior year, and long-term averages.
“Growers can use this information along with their farm situation to assess the risk to their own crops,” Leybourne explained.
Milder geographic locations, sheltered fields at lower altitudes, proximity to the coast, and early sowing all increase vulnerability to BYDV infections. To assist management decisions, the Agricultural and Horticultural Development Board (AHDB) launched a digital BYDV tool. Growers can input their field location and planned sowing date—or post-emergence date—to receive a disease risk summary and guidance on when to take action.
Pyrethroid Application Guidelines
Combining monitoring data with field scouting helps farmers determine whether intervention is necessary. Where aphids are present and infection risk runs high, a single pyrethroid application at the two to three leaf stage effectively controls the insects and limits BYDV spread for October-sown cereals.
For higher-risk September-sown crops, a second spray may be justified to safeguard yields if mild, settled conditions persist late into the autumn. However, both CAFRE and AFBI advise against multiple pyrethroid applications, noting they accelerate resistance in aphid populations and complicate future BYDV management.
Where to plant barley and how aphids spread virus?
Where is winter barley planting currently most viable in Northern Ireland?
Planting is especially viable in areas such as County Down, where growers achieve high establishment rates due to excellent recent soil conditions.
How do aphids transmit Barley Yellow Dwarf Virus to cereal crops?
Infected aphids transmit the virus by feeding on newly emerged seedlings. These pests arrive either as non-winged insects from field margins and crop residues or as winged migrants traveling from greater distances.
What guidance do CAFRE and AFBI provide regarding insecticide use?
Authorities recommend a single pyrethroid application at the two to three leaf stage for high-risk crops, while warning against multiple sprays to prevent the development of pyrethroid resistance in aphid populations.
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