12 June 2025

Variability and BYDV evident in spring barley crops

Crops Specialist at Teagasc, Ciaran Collins assesses the performance of spring barley crops, highlighting some variability and a rise in BYDV incidence, especially in later-sown crops.

Spring barley is a bit of a mixed bag this year, largely depending on when the crop was sown and when nitrogen was applied. The best crops so far are those that were drilled early and received their main split of nitrogen before the rain came. On the other hand, crops sown later struggled through the dry spell, which had left soils in the south and southeast with moisture deficits of about 40 mm on well-drained land.

In early sown crops, shoot numbers of 800 to 900/m² suggests good yield potential. However, later-sown crops have fewer shoots and shorter plants overall. 

Thanks to the ongoing dry weather, disease pressure has stayed low this season. However, it has been tricky to get the final fungicide spray on at the ideal time (awn emergence), due to showery and windy conditions. That said, the lower rainfall is helping reduce the risk of diseases like Ramularia. 

Barley Yellow Dwarf Virus

The threat from Barley Yellow Dwarf Virus (BYDV) appeared to be low this year thanks to earlier sowing dates. Up until about a week ago infection levels were low, but many advisors have reported seeing BYDV symptoms in the last 7–10 days. These later-than-usual symptoms are showing up as yellowing on the flag leaf and second leaf. 

Figure 1: BYDV symptoms in spring barley

The level of infection varies across the country, with higher levels reported in Tipperary and Donegal. However, since this infection has appeared relatively late, possibly due to later infection, it’s not expected to cause significant yield loss. 

Initial reports suggest that BYDV is worse in later-sown crops (though it is present in earlier ones as well). It’s still unclear if earlier insecticide treatments had any significant effect on infection levels. Poorer crops do seem to be more affected. 

Researchers at Teagasc are currently gathering more information on this in terms of the level of infection, aphid movement, virus type and weather patterns and a clearer picture will emerge over time.

Crops and Technology Open Day

Teagasc’s ongoing research in the area of BYDV will be discussed at the Teagasc Crops and Technology Open Day, taking place on Wednesday, June 25.

Find out more and plan your visit to the Crops and Technology Open Day here.