Barley Yellow Dwarf Virus (BYDV) is running rampant through winter and spring cereal crops nationwide, according to Teagasc crops specialist, Shay Phelan.
Phelan spoke about the risk of the virus spreading further at a Teagasc Crop Walk, held in north Co. Dublin yesterday (Friday, May 10).
While research is ongoing, Teagasc is unsure how the disease-causing aphids are getting on to crops in the first place.
“Suction traps in places like Teagasc Oak Park had not caught significant numbers of flying aphids over recent months.
“So this leaves open the possibility of grain aphides physically walking through fields and/or over wintering on individual cereal plants,” Phelan said.
This type of behaviour on the part of the aphids has not been recognised up to this point, according to Phelan.
“BYDV is very apparent in spring and winter cereal crops south of Dublin.
“The possibility of a similar scenario being the case across the rest of the country is very real,” Phelan said.
“In reality, we are talking about a very fluid situation, which will be a key focus of new research within Teagasc,” he added.
BYDV
According to Teagasc, BYDV can have differing levels of crop impact with yield losses of up to 80% possibility.
However, this would only be in the case of very severe infections. The average loss figure is in the region of 30%.
In the meantime, cereal growers are being advised by Teagasc to spray any spring barley and wheat crops with an insecticide as a “matter of priority”.
“The best time to put on an insecticide is when crops are the four-leaf stage.
“One application of an active product will suffice. The insecticide should be applied at full label rates,” Phelan said.
In-crop monitoring is essential before an insecticide is applied to check if aphids are present.
Growers should inspect headlands first, because aphids are three times more likely to land near headlands than further out the field.
The risk periods for BYDV infection coincide with milder temperatures and the associated migration or reproduction of aphids.
Normally, earlier sown crops are at the highest risk of infection and it is difficult to avoid insecticide application in these scenarios.