West: Don’t be tempted to delay T2 fungicide

Since last writing the weather has improved although at times it has still been abnormally cold for the time of year. We have had enough rain and there has been sunshine as well.

With rape crops in flower, the patchiness of many crops is now more evident than ever. Patches of pigeon and rabbit damaged crops are also flowering significantly later than undamaged parts of fields, making decisions around sclerotinia spray timings quite difficult.

Most rape crops have now received a sclerotinia spray, with a second top up due at the end of flowering. Crops in general are a lot shorter than usual, with a more open canopy. It remains to be seen what effect this will have on yield, but hopefully it will be positive, as all too often rape crops carry too much canopy.

Winter wheats have, as expected, dropped a leaf and produced final leaf three at GS 31 rather than 32. This now means that most crops are not so far behind in terms of development as they were a month ago. They are now about 10 to 14 days behind where we would normally expect them to be at this time of year.

Just as final leaf three was emerging we had a week of very wet and windy weather which has meant that the T1 applications on many units have been delayed until leaf three is fully emerged or in some cases, final leaf two is well on its way out.

Where there has been a weather delay there will be a temptation to then delay the T2 application to get “Best value” out of the T1 application. I would urge growers NOT to go down this route. The T2 application is the most important one of the season. If, through weather delays, the T1 has been mis-timed there is no earthly reason to then go on and deliberately put the T2 application on at the wrong time.

The crop will be under more disease pressure where T1s were delayed and the lesson from last year was that this can be very serious if the weather continues to favour the development of Septoria. It is quite noticeable that there are higher levels of septoria in crops that did not receive a T0 or only received a contact fungicide such as Bravo at this timing, rather than a triazole or triazole/contact fungicide mix.

Winter barley crops continue to look well with most crops, at the time of writing, having their ears emerging. Of all the winter crops the barley seems to be more “On track” in terms of development although there is quite a lot of variation depending on drilling dates. Most crops have now either received or are on the verge of receiving their T2 fungicide application. Where yield potential looks OK this will be a mix of Triazole and Strobe or SDHI.

Rynchosporium which is usually our most prevalent disease in winter barley appears well controlled so far, helped by a relatively dry March.

Spring barley is generally looking extremely good at the moment, which is just as well, given the much larger than usual area sown to this crop this year. At the time of writing most crops are at mid-tillering, with a few of the earlier drilled crops having made it to GS31.

Broad-leaved herbicides have been applied and have worked well. T1 fungicides are now being applied, as we have now had a week of wet weather which will help the development of rynchosporium.

The next month is going to be critical to the success of most crops. We can do nothing about the weather but we can do something about correct input timings. I would urge all growers to be particularly diligent about getting inputs applied at the correct timing. Crops have struggled this year and need all the help they can get in order to produce a good yield.

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