Malting barley crops sown out in March should not need an insecticide to control Barley Yellow Dwarf Virus (BYDV).
That was the clear view expressed by Eoin Lyons, the Teagas/ Boortmalt joint programme advisor on a recent edition of the Tillage Edge podcast.
“The majority of crops were sown in March and will be coming up before that mid-April timing,” he said. “So in reality, there should no requirement to use an insecticide this year.
“However, there will be exceptions. Crops sown out in coastal areas would be one. These are high pressure areas, where BYDV is concerned.
“If an insecticide is required, it should be applied at the two to four-leaf stage or Growth Stage 13 to15.”
Nitrogen on barley
According to Lyons, nitrogen (N) remains a vital component of any spring barley crop management plan.
“A number of trials have been carried out by Teagasc, looking at different N rates for malting barley,” he added.
“For brewing barley, an N application rate of 150kg/ha will be sufficient. This figure reduces to 130kg for distilling crops.
“Many growers will put between 40kg and 50kg of N into the seed bed. So, really, we are looking at topping up from these levels.
“The remainder should be applied in a single split at an early stage of growth. This helps ensure a lower protein content within the crop that is eventually harvested,” he said.
Many growers will opt to apply the second split of N to malting barley just as the tram lines become visible.
However, given that many crops have been sown early this year, Lyons is advising that growers have the option of waiting until the two to four-leaf stage.
“We have also carried out a lot of work this year, looking at the impact of catch crops on subsequent N availability for malting barley.
“In principle, catch crops can increase N availability for malting barley that directly follows it. But, in reality, it may not be that much e.g., we found that catch crops sown in August of last year managed to take up as much as 50kg N/ha.
“But the amount of this N that can be directly utilised by a malting barley crop that follows is in the region of zero to 40%.
“There are a number of factors that influence this utilisation figure. The date of termination of the catch crop would be one. Another is the actual utilisation of the catch crop. Had it been grazed, for example?”