The spell of glorious weather experienced over the last couple of weeks has made a huge difference with all of spring cereal crop now emerged and the early ones at mid tillering and beyond.
To minimise the effects of competition on the crop and optimise the level of weed control, herbicide application should be carried out once all weeds have emerged but are still small, and before they begin to compete with the crop for nutrients and light.
Carrying out the weed control when they are at the two to four leaf stage is much more effective especially on difficult weeds such as fumitory and knotgrass, rather than delaying to coincide with the 1st fungicide application.
Winter cereals for the most part are racing through the growth stages, while the majority look remarkably well, growth stages range hugely particularly in wheat, reflecting the extended sowing period throughout the autumn and winter months. Disease levels are variable with the more advanced crops showing higher levels of Rhynchosporium or Septoria.
Winter barley varies from awns appearing to heads fully out on the most advanced. Disease levels are generally low, with Rhyncho contained to the oldest leaves. However Ramularia is now appearing onto the upper leaves of some crops and this disease must be robustly controlled at the T2 timing along with Rhyncho, Net Blotch and Mildew.
Winter wheat crops range from those at third node to flag leaf fully out. Septoria lingers on the lower leaves of all crops, and is rapidly moving up onto new growth in some. Yellow Rust has been found in recent weeks and surprisingly appearing in the variety Graham.
Properly protecting the top three leaves and ear at T2 is critical to yield and profit - foliar disease not controlled effectively at this time will hasten the senescence of these leaves during grain filling, and therefore impact adversely on yield and grain quality. This treatment will extend canopy duration therefore increasing the amount of starch produced for grain filling, and increase grain storage capacity leading to higher thousand grain weight (TGW).
Managing disease resistance and maintaining reliable control with the fungicide options available means using a range of different actives over the course of the growing season. Ensure there are a number of different modes of action in the tank at every treatment, that way maximising the range of strains sensitive to the mix. SDHIs are now essential partners to protect the triazoles and maximise the yield in all but the most backward crops, adding some curative as well as preventative activity. Having a completely different mode of action to the triazoles, they will improve the kickback activity of the treatment, as well as widening the spectrum of disease strains controlled. It is good practise to use different actives from within the same chemical group at the different spray timings.
Where possible, use different triazoles and SDHIs at each fungicide application over the course of the season to give the widest possible activity across the different strains of fungi of all diseases.