Apply T0 spray targeting yellow rust to wheat crops now - agronomist
Teagasc tillage specialist Shay Phelan is confirming that the time to control yellow rust in winter wheat crops is now.
He explained: “We know that 75% of the winter wheat crops planted out in Ireland last autumn are susceptible to the yellow rust breakdown that was confirmed last year.
“The best way of addressing this issue is for growers to apply an appropriate T0 spray over the coming days.
“If yellow rust is already active within a crop, azole of strobilurin chemistries will be required to address the problem."
Significantly, Teagasc’s Crops and Returns booklet for the 2025/2026 growing season takes specific account of the need for wheat growers to implement a four-spray fungicide programme over the coming weeks.
Beyond the T0 stage, the focus switches to septoria control.
“It is imperative to keep Leaf Three clear of disease in order to maximise the yields achieved with winter wheat crops," Phelan said.
“So, it is important that cereal growers recognise when this growth stage is about to be achieved and to respond accordingly.
“Within all spray programmes, a mix of fungicide chemistries should be applied. Taking this approach ensures that resistance issues are minimised.”
The Teagasc representative took part in a recent CAFRE business sustainability group (BSG) crops walk on the south Co. Down farm of cereal and oilseed rape grower Shaw Hanna.
Phelan pointed out that wheat crops have greened up well across the country over the past week or so. However, they will not require their first split of nitrogen until around the middle of March.
Potash
Teagasc recommends that phosphorous and potash should be applied to heat crops in tandem with the first nitrogen split as per soil index data.
Shay Phelan noted that that adding a proportion of a crop’s potash requirement at a slightly later growth stage had a straw strengthening impact.
This effect had been confirmed courtesy of research carried out at Teagasc Oak Park.
The option of applying slurries to winter cereal crops during the spring months should also be considered, as they are valuable sources of nitrogen, phosphorous and potash.
Plant Growth Regulators should be applied to winter wheat crops at Growth Stage 31. Split applications should be considered with crops that have a high degree of lodging risk.
If temperatures are below 8°C, then an adjuvant should be applied to the tank mix.
