The cold weather has finally brought the GAI of oilseed rape crops back to somewhere close to where we would expect them to be at this time of year. Over the last month they have lost 0.75-1.0 GAI, which means that the forward crops are now allowing carbetamide applications to hit the ground where it’s needed.
Two nights dropping to -10C have helped Fox (bifenox) to work on charlock. I was worried about how some crops going to look where there was more charlock than rape.
With the cold weather the pigeons are just starting to arrive but numbers are still far lower than we would normally expect. While the cold weather lasts I’m expecting numbers to increase. As long as they are not eating the crown of the plant they won’t be doing any major damage, however be ready to control numbers before they do damage.
Cereals that had high levels of mildew, and in places rust a month ago now look a lot cleaner, again due to the cold weather. I have found crown rust in forward oat crops last week. The downside is that in wheat, the levels of septoria are now clearly visible – I think a lot of it was there before but was being ‘hidden’ by the mildew.
Disease risk is still high for this year, so unless the cold weather lasts for most of this month then T0 sprays will need to be robust and very well timed. The longer the cold weather lasts, does mean that timings for the start of disease control programmes will become more normal. At the moment things may well start considerably earlier than we expect.
More manganese deficiency is visible than I would normally see, especially on heavier land and on barley crops. These will want treating as soon as possible, maybe before we do anything else. Correcting trace element problems will also help to reduce stress on crops which in turn can reduce disease levels especially mildew.