Concerns about input costs and rust control are pushing agronomists to recommend an epoxiconazole-based fungicide for wheat T1 sprays, according to a straw poll of more than a dozen agronomists carried out by Farmers Weekly.
While many agronomists are not finding yellow rust infections yet this spring, Prime Agriculture‘s Bill Barr said he originally saw symptoms in Oakley on some of his east Northamptonshire farms six weeks ago. “It disappeared as older growth died away, but has popped up again recently. We have ideal temperatures, albeit maybe a bit dry, for it now.”
T0 fungicides should have kept it under control – most of his recommendations were applied last week, he said on Tuesday [20 April]. But he wants what he considers the strongest material against rust and septoria – epoxiconazole – to form the basis of his T1 spray. “It is the best fit for the rust-susceptible varieties we have in the ground this year.”
He had mainly discounted other options, such as Cherokee which, although good on rusts, was weaker against septoria, and Proline as it was “not the strongest material on rusts”, he said. “Proline plus chlorothalonil is also quite expensive compared with epoxiconazole plus chlorothalonil.”
He hoped most of his T1 recommendations would be applied from next week when final leaf three was around two-thirds emerged. “Where we have eyespot, or eyespot-susceptible varieties, it will probably be Tracker plus chlorothalonil.”
In the south, Richard Cartwright of Chichester Crop Consultancy reported low foliar disease pressure, but was concerned by eyespot, in particular in early drilled first wheats. That could push him towards treating those crops with a boscalid-based T1 in the next 10 days, even though T0 fungicides only went on last week.
“Tracker is a better option than Proline – it is more consistent in its results, and you need to get every last per cent control you can against eyespot as it is a tricky disease to control.”
Where eyespot wasn’t an issue and there was no requirement for further growth regulation, he was considering delaying T1s for at least a couple of weeks, in light of forecast continued dry weather and low disease pressure.
“We’ve had very little rain splash recently or forecast in the next 10 days, and I haven’t seen any yellow or brown rust yet.
“So where they’ve just had T0 I think we can probably delay until GS32-33 rather than the conventional T1 timing, and coincide with leaf two emerging,” he said.
Bryce Rham, based in Shropshire, was one of the few agronomists contacted by Farmers Weekly to be considering using Proline at T1, recommending it on varieties with an eyespot risk and low disease resistance, such as Humber and Einstein.
Lower eyespot risk varieties, such as Grafton and Batallion, would also be applied with Proline at a lower rate at T1, he said.
Rust risk on all wheat is covered off by adding a strobilurin: Comet on first wheats and Amistar Opti in second wheats. “Adding a little strobilurin means you know it won’t get rust.”
Varieties with a higher risk of eyespot or lower septoria risk such as Alchemy, JB Diego and Oakley, would get a Tracker plus strobilurin T1, he said.
Opus £email@example.com litres/ha
Rubric £firstname.lastname@example.org litres/ha
Proline 275 £email@example.com litres/ha or £firstname.lastname@example.org litres/ha
Tracker £email@example.com litres/ha