With a continuation of wet weather and a lot of earlier drilled wheat crops, septoria is building up very quickly in many fields. The situation is at least equal to, if not worse than last year and we know how difficult septoria was to control last year.
A T0 application containing a multisite and a triazole will have to be a given this year if we are to stand any chance of getting on top of the disease. Combine this situation with the fact that triazoles continue to be less effective against the disease and we have the potential for a real problem season. A prolonged dry spell would help the situation.
The evidence of the last few years would support the view that when it comes to T1 an SDHI should be in the mix, along with a robust triazole dose. In order to keep the disease pressure as low as possible early nitrogen applications should be made no earlier than is really needed and the dose rate kept to appropriate levels. Encouraging further unwanted tillers and leaf can only have a detrimental effect on the crop.
Winter barley crops are looking well, but are also carrying high levels of disease with rhynchosporium and brown rust both in evidence. Again a T0 application will be of benefit in bringing the disease under control. The choice of material for T1 is less clear in barley. Strobilurins continue to give good yield responses in barley, so the case for SDHIs is less strong than in the wheat crop. In 2014, however, there were some very large barley yields where SDHI fungicides were used and it is not clear if this is down to better disease control or just a good season.
Oilseed rape crops continue to vary from crop to crop, with some remaining very forward and others less so, particularly where there has been a major pigeon strike. Making the correct nitrogen applications in crops that were large and are now small can be very difficult, as a lot of the nitrogen that was locked up in the crop has been removed from the fields by the pigeons.
At the moment in the Southwest we have some crops that have a relatively small green area index (GAI), but plants with a massive crown and root system and other crops with the same GAI that are made up of small late drilled plants. It stands to reason that the smaller less developed plants will require more nitrogen earlier than those that are large, but have been partially defoliated.
Should the weather dry up we will be into the spring drilling season in the blink of an eye. Let’s hope that this goes well and that the spring crops will have plenty of potential.