DIFFICULTIES getting on the land to apply T0 fungicides in winter wheat could mean T1 fungicides will need to be made more robust as a way of compensating this season, says Syngenta field technical manager Simon Roberts.

As a result, the company is offering guidelines on how its chlorothalonil-based fungicides Bravo and Cherokee, which growers often buy in for T0, can be incorporated at the T1 timing.

“Where growers are unable to apply their planned T0 fungicides – for example because it’s not possible to get on the land, or for workload reasons, or because crops progress through growth stages too quickly and the T0 timing is missed – there could be a need to fortify T1 disease control to account for this,” Mr Roberts explains.

“Already this season there has been strong interest in using the powerful disease control of a new-generation SDHI fungicide at the T1 timing. So if T0 is missed out, the argument for doing this becomes even stronger.

“But to take this a stage further, where growers had been planning to use Bravo or Cherokee at T0, then either of these can be tank mixed with Seguris if that is your planned T1 SDHI fungicide. The chlorothalonil component in either Bravo or Cherokee will give added activity against Septoria tritici and provide a resistance management strategy,” he adds.

As an example, Mr Roberts says 0.75 l/ha of Seguris can be mixed with 1.0 l/ha of Bravo. Alternatively, 0.6 l/ha of Seguris + 1.25 l/ha of Cherokee is a good mix, he adds, providing a robust dose of triazole again with a chlorothalonil component.

“Applying a new-generation SDHI fungicide at T1 is worth considering whether or not a T0 fungicide has been used,” continues Mr Roberts, “in order to give the crop long-lasting protection.

“On-farm results from last season where Seguris at T1 was compared against more traditional chemistry showed that the protection from Seguris was still visible when the crop came into ear,” he added.