08 November 2024
Assessing BYDV risk – the important factors to consider
Ciaran Collins, Crops Specialist at Teagasc, takes a closer look at Barley Yellow Dwarf (BYDV) virus, sharing insights from experiments completed at Teagasc Oak Park and factors to consider when assessing BYDV risk.
Recent Teagasc Barley Yellow Dwarf Virus (BYDV) experiments on the early planting of winter barley have shown that:
- Early sowing increases BYDV risk;
- Later sowing gives similar or better yield than early sowing where BYDV is a risk;
- Selecting a tolerant variety reduces risk of yield loss to BYDV when sown early where BYDV is present.
Other important factors to consider when assessing BYDV risk are mild weather and whether a ‘green bridge’ is present or not, as volunteer cereals and grasses are host species for the grain aphid.
Insecticide application should be targeted. Cereal crops emerging in November are at a much lower risk of BYDV than those that emerged in October. Check if aphids are present in the crop. Look at the headlands. Aphids are three times more likely to land near headlands than further out. If they are present, apply an insecticide at the 2-3 leaf stage of the crop.
Table 1: BYDV risk and control
| Sowing | BYDV risk | Control action |
|---|---|---|
| Early sown (not recommended) | High | Pyrethroid at 2-3 leaf stage and pyrethroid early November |
| October sown | Medium to high | Pyrethroid early November |
| Emerging after November | Low | Control need in mild winters, where aphids are plentiful, or in high risk areas |
The above article first appeared in the November Teagasc Tillage Advisory newsletter. For more key advice on weed and slug control and fertiliser planning, access the full publication here.
Additional information
Dr. Louise McNamara, an entomologist from Teagasc, joined a recent episode of the Teagasc Tillage Edge podcast, where she outlined the best strategies for controlling BYDV in winter cereals.
Listen in below:
Also read: BYDV control programmes and tolerant varieties