South: Watch out for light leaf spot

At last the cold snap and hopefully the main of the winter is over. It is the worst I have known for the last 30 years with snow covered fields and roads like ice rinks. I ventured out one day back in January but after an hour on the road I hastily retreated back home.

All crops except the middle of October late-drilled crops of Oilseed rape have come through the weather pretty well. Once these smaller crops have started to grow and the temperature is above 8C then it would be advisable to apply some early nitrogen to encourage leaf growth and root development. There is a  large amount of phoma present on the untreated crops of rape and variable amounts can also be seen on the new growth in some of the autumn treated crops.

These crops will need urgent treatment with a robust rate of a fungicide such as Capitan (flusilasole) as soon as weather conditions allow. Also, look out for light leaf spot, which is at level higher than I have ever seen in my 34 years of experience in the field. Where light leaf spot is noticed then use Proline (prothioconazole) or add carbendazim to the Capitan.

Winter cereal crops have come through the winter well and are betweenGS 24 and GS 27. Some fields of wheat and barley did not get an autumnherbicide spray. It should now be a priority to complete theseherbicide programmes as soon as the temperatures rise and the groundconditions allow to travel before the weeds get too large.

When applying Atlantis (mesosulfuron + iodosulfuron) remember the newguide line not to mix  it with more than one other product, although Ihave to admit that I have noticed no change in the activity of thismaterial with the multiple tank mixes that I have used in the past. Oneexception is Chlorothalonil which has to be avoided as a tank mixpartner to avoid poor black grass control.

Mildew which was carried over from the autumn has now died on the oldleaves of wheat and there is little sign of any new lesions ofseptoria. Winter barley varieties  Cassata and Pearl are showingsymptoms of net blotch.

It is time now to consider taking cores of soil to test for soilnitrogen. I suspect that levels will be low this year considering thehigh level of rain last autumn.

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