South: Crops keep growing, but so are grassweeds

Things are looking very different to last year. By the end of January 2013 we had had cold weather and snow which had just about cleared down here. This year it has been relatively warm (av. temp 5.6C) but very wet, with about twice the amount of rain we would normally expect for the month. Soil temps are 3-4 degrees at 10cm whereas last year they were just above freezing.

This means that most crops haven’t stopped growing since they came through the ground.  Even late drilled wheat after maize has one or two tillers. The disadvantage is that the blackgrass and brome hasn’t stopped growing either. Those fields that haven’t had anything applied since the pre emergence sprays have grassweeds that are tillering very strongly.

Those that have had an autumn application of Atlantis (iodosulfuron + mesosulfuron) or Unite (flupyrsulfuron + pyroxsulam) are looking very clean.  If the weather stays warm, fields that need grassweed control will be the first priority when the ground dries up enough to be able to travel.

The other big issue to remember is that we haven’t had a good cold spell to reduce the BYDV risk. Temperatures of  -6C will kill off 50% of aphids, but they will breed in temperatures down to 4C. We’ve had one night that got down to -6C which will have reduced numbers, but the daytime temperatures have been warm enough for numbers to build up again. Many autumn insecticide sprays weren’t able to be applied so it may well be prudent to apply another insecticide when conditions allow.

Disease levels are much higher than normal, especially yellow rust and septoria.  Unless we get a substantial cold spell, enough to kill off diseased leaves, the yellow rust risk will remain high. With the level of septoria also being high at the moment I think T0 sprays will need to be robust to easy pressure on later applications.  Rhynchosporium and net blotch, though visible, aren’t too bad on barley, but rusts are easy to find. Barley crops are very thick this year, so are likely to respond well to T0 fungicide applications.

Oilseed rape has established very well.  GAIs of around 1 are typical with some fields being close to 2. Like the cereals the rape hasn’t really stopped growing.  Light leaf spot is non existent and phoma levels are low if at least one autumn fungicide was used.

Soil N testing is being done at the moment, but no results are back. It’ll be interesting to see how high or low they are. Soil has stayed warm and it’s been wet, which makes me think they should be low. But crops are growing and still look green which suggests that available N is relatively high. Time will tell…..

See more