April
What's happening in wheat in April
Throughout March the mostly warm, calm, and dry weather has allowed plenty of progress to take place, including finishing off grass-weed control, and making a start on T0 fungicides.
Disease pressure is currently average for this time of year, although Septoria and Powdery Mildew can readily be found in crops, and Yellow Rust is increasingly being found in some varieties.
T1 fungicide timings will fall, for most, within April. It is vital to get the timing right, since this is the main building block for season-long disease control, focusing on Septoria, Yellow Rust, Eye spot, Powdery Mildew, and reducing Fusarium infection. Septoria and Yellow Rust have the greatest impact on yield, so the choice of product and rate at T1 is crucial.
However, timing is just as important. Aim to apply T1 fungicides when leaf three is at least three-quarters or fully emerged. Try to time applications so that the gap between T1 and T2 applications is around three weeks to avoid T1s running out of steam if Septoria and Yellow Rust disease pressure is high.
Varieties with good resistance (rated seven or higher) that were drilled in November or later, are likely to be under less disease pressure and growers have the option of either AscraXpro at 1 L/ha or Aviator 235Xpro at 0.8 – 1 L/ha.
Crops that will be more susceptible to Septoria (drilled earlier and/or with lower resistance ratings), or any crops that didn’t receive a protectant fungicide at T0 should consider using a higher rate of AscraXpro at 1 – 1.2 L/ha. The choice of rate will also be dependent on the levels of disease in the crop at the time of application.
Latent Septoria and Yellow Rust can now be identified using Bayer’s CropCheck initiative, before disease is visible in the crop. This can help to play a part in decision making. Find out more about CropCheck and look at the National Snapshot Live results to see how disease is progressing in commercial wheat fields in your area.
Eyespot and Fusarium can sometimes be overlooked at T1, but most varieties in the ground this year have low tolerance to Eyespot in particular. A wet and warm April could drive disease, particularly in second wheats, and wheat drilled into last season’s stubbles where inoculum is present in the trash. Wet weather last season drove Fusarium infections, with high levels of inoculum carried over to this season’s seed, which could cause issues later in the year.
For both Eyespot and Fusarium reduction, AscraXpro at 1 L/ha or Aviator 235Xpro at 0.8 L/ha will provide good levels of protection.
Priorities now:
- Apply T2 fungicides in a timely fashion
- PGRs can be added to T1 applications
- Apply a final dose of nitrogen to all wheats except those destined for milling
- Finish grass-weed control programmes if not already complete