Co. Down-based agronomist, Richard Owens, has confirmed the high threat of barley yellow dwarf virus (BYDV) in winter cereals planted out across Northern Ireland over recent weeks.
He said: “The current weather conditions are encouraging a strong growth in aphid populations. In turn, this enhances the BYDV risk.
“In tandem with this, many growers pushed on and applied a pre-emergent herbicide almost as soon as the crops were sown out. This is a very strategic step, given the fact that it acts to effectively control annual meadow grass levels.”
According to Owens, annual meadow grass has the potential to wipe up to 1t/ac off the final yield achieved by cereal crops.
“However, these initial sprays did not contain an insecticide. Since the introduction of the ban on neonicotinoid seed dressings, spraying cereal crops at the three-leaf stage with an approved insecticide is the only way of controlling the BYDV risk.
“From what I can gather quite a number of autumn sown crops have not yet been sprayed with an insecticide, which will increase crop exposure levels to BYDV.
“But we will have to wait until next spring to find out if this is really the case,” he added.
BYDV
The agronomist has confirmed high levels of winter cereal plantings across Northern Ireland, relative to 2023.
“This is particularly the case where winter barley is concerned. Acreages of winter have been consistently on the decline over recent years.
“Quite a number of growers have opted to plant out barleys for which BYDV resultant claims have been made,” he said.
The six-row variety, Integral is a case in point.
“The jury is out as to whether these BYDV resistance claims actually hold up.
“However, the coming weeks and months will tell the real story, given the high levels of disease threat that exist at the present time,” Owens continued.
Meanwhile, Agri-Food and Biosciences Institute (AFBI) staff monitor aphid migration patterns in Northern Ireland.
They make use of a 12.2m suction trap that collects aphids across a 100km radius.
Weekly trap catches are examined for the presence of aphid species that are pests of cereals and a bulletin is circulated to provide growers with trends in aphid activity.
Late-sown spring crops are most susceptible to infection, owing to the prolonged exposure to migrating aphids.
Early-sown winter crops, particularly in mild autumns, are also most susceptible as vulnerable growth stages are exposed for longer to migrating aphids such as the bird cherry-oat aphid, an important vector of BYDV.
Early summer infestations by grain aphid or rose-grain aphid may cause substantial yield loss. Aphid infestations before flowering may reduce grain numbers: subsequent infestation will reduce the size of the grain.