It’s been autumn since September here in equatorial Lincolnshire and apart from half a dozen subzero nights since December, there’s no sign of winter on the horizon. As a result, apart from a couple of weeks since Christmas, soil temperatures have been sat around that magical 4C mark for most of the winter and crop and weed growth alike have continued – latterly, albeit slowly.
It’s also clear that soil nitrogen is being mineralised and released, because apart from the most waterlogged areas, cereal and oilseed rape crops look green, well fed and healthy – good job, because there’s no chance of travelling to apply any fertiliser!
Autumn residuals have generally worked well in cereals, but it’s obvious that we’ve had several flushes of blackgrass since September, so some hard choices will have to be made in fields this spring – particularly where ALS-inhibiting materials have already been applied and a carpet of blackgrass remains.
Oh yes, and just because your neighbour is out spraying Atlantis (iodosulfuron + mesosulfuron) on a wet crop, just before a shower, on a windy day using air induction nozzles, or at 6 o’clock at night as the dew falls, it doesn’t mean he’s right – it means that somewhere there’s a brow-beaten agronomist rolling his eyes!
The yellow rust, septoria and mildew that was widespread in wheat pre-Christmas is still there, but thankfully it’s got no worse and T-zero should sort it when that time or opportunity comes. Incidentally, harvest 2007 was one of the worst years on record for yellow rust and I haven’t seen levels as high going into Christmas since – until this season.
The temperature and rainfall data since last November mirrors the same period back in 2006/7 almost exactly and, with so many varieties in the ground which are susceptible to the far more aggressive “Warrior” race of yellow rust already showing symptoms, the potential for a bad yellow rust season is huge. T-zero will be an important timing this year, not just for septoria, but also for Yellow rust, so choose your weapons wisely – if you get it wrong early season with these diseases, you can’t spend your way out of trouble later – that’s like standing in a bucket and trying to pick yourself up by the handle!
Disease levels in oilseed rape following applications of prothioconazole last autumn remain exceptionally low and therefore, OSR fungicides are in no way an imminent priority. Propyzamide has finally started to show signs that it is working, although it’s taken all of 12 weeks in some cases and, even though it’s relatively mild for the time of year, it’s still way too cold for the use of Galera – this should be applied only once soil temperatures rise and active weed growth is underway.
I took 17 mm of rain in December, 78 mm in January and so far 25 mm in February – when you look at how the rest of the country has fared over the last few weeks, that almost constitutes a drought!