This is the time when management steps taken by tillage farmers will determine the disease status of winter wheat crops.
According to Teagasc, winter wheat needs that little bit of extra attention now in order to build a big and disease-free canopy.
If this can be achieved, it means that the maximum amount of ambient light will be captured by the growing plants.
Some 80% of the final yield generated by wheat crops comes from the top half of the canopy. That means having a good clean foundation is important.
Growers should complete the main nitrogen (N) application before growth stage (GS) 32. This generally equates to half the total amount of N for the crop if a three-split programme is being used, and is typically in the range of 100-125kg/ha.
The third split should be applied at flag leaf stage.
Plant growth promoter (PGR) should be applied to winter wheat crops by first node (GS 31).
Options here include CCC 75%: 2.0L/ha + Adjuvant; K2: 1.8L/ha; CCC: 1L/ha + Moddus: 0.2L/ha or Meddax Max: 0.2kg/ha.
Temperatures in excess of 8°C will be required to secure maximum effect from a PGR.
The dry weather of March will have helped to reduce the risk from septoria somewhat. But in high-risk sites with, for example, early sown or dirty varieties, then a leaf 4 (T0) application of a fungicide to keep septoria at bay is probably justified.
If possible, growers should avoid using an azole – options include Folpet or sulphur. Where yellow rust is an issue, it will be a case of using Comet: 1.0L/ha.
A Leaf 3 spray (T1) can be applied when third last leaf is fully emerged.
It is now known that the current fungicide choices do not have the flexibility that used to be available a number of years ago. So timing on the application of the different fungicides needs to be precise.
Growth stage may not be an accurate indicator of the actual leaves present in the crop, so dissecting plants and identifying the correct leaf to apply the first fungicide is critical for optimal septoria control.
In many crops, it could still be very late April or early May before the timing is correct – even after the mild spring.
Fungicide choices here include Folpet: 1.5L/ha or sulphur, for example, Thiopron: 3L/ha + 80-100% rate (Revystar XL, Univoq, Jessico One, Ascra Xpro, etc.).
Being able to identify crops at the Leaf 3 stage is very important.
