According to Syngenta UK head of technical, David King, the combination of healthier grain prices but increased fertiliser costs over recent years has raised the financial stakes of growing crops – so any ‘mistakes’ that allow yield-robbing diseases to gain a foothold can pose a bigger crop margin threat.
“Grain prices have declined slightly recently, but they still remain strong,” says Mr King, “and clearly appropriate nitrogen (N) use is essential for crops to reach their full yield potential. However, to get maximum benefit from that fertiliser expenditure, it’s essential to minimise the amount of yield that’s lost to disease.
“The flag leaf in winter wheat contributes the most to yield, at about 43%, so keeping this clean of disease is paramount, but waiting until T2 to do this is missing the boat. Disease prevention starts earlier – potentially at the T0 timing, but certainly at T1.
Think of a T1 fungicide as a firebreak to restrain the upward spread of infection to leaf two and the flag leaf. By using an effective T1 fungicide to achieve this, you stand to get better results from your T2 fungicide because it will be used more preventatively,” he adds.
Mr King says although recent years have seen a greater appreciation of the importance of T1 – partly driven by increased awareness of difficulties ‘controlling’ Septoria tritici later, and bitter experiences of managing yellow rust – the need to get the best return from fertiliser brings its importance into even sharper focus. “It’s vital to protect that fertiliser investment,” he stresses.
“Yellow rust has become more unpredictable. It can flare up rapidly and we’ve seen how suddenly variety resistance ratings can tumble. Yellow rust also isn’t just an Eastern counties disease.”
Where yellow rust poses any kind of threat around T1, Mr King suggests that the SDHI-based fungicide Elatus Era is a ‘no-brainer’. AHDB dose response curves demonstrate its outstanding activity against yellow rust, he says, although to pigeon-hole it as a rust-only treatment is to miss out on its other benefits.
Chief among these, he says, include the way its active ingredient (benzovindiflupyr also known as Solatenol) has been shown to interact with the leaf – which is important when it comes to managing Septoria tritici and for providing persistence.
As well as using an effective SDHI at T1, Mr King says adding the multi-site fungicide folpet is also an important consideration for managing Septoria tritici resistance.
“Nitrogen gives one of the best returns among inputs, but it’s important to protect this investment by minimising disease. An effective T1 fungicide becomes even more important if you’ve not controlled disease at T0,” he adds.
For more information visit: www.syngenta.co.uk/elatus-era
Amistar (MAPP No. 18039) contains azoxystrobin. Elatus Era (MAPP No. 17889) contains benzovindiflupyr and prothioconazole.
Use plant protection products safely. Always read the label and product information before use. For further product information including warning phrases and symbols refer to www.syngenta.co.uk
