West: Sticky going for spraying

Rain over the last few days and a hard frost this morning will result in sticky soil conditions for those with spraying still to do.

Most crops are now well established, with early wheat at two tillers and oilseed rape anything from six leaves to knee high. Even the oilseed rape on the higher ground of the Cotswolds, which for a long time has struggled, is now looking fit enough to survive the winter.

Unfortunately the blackgrass also is growing well but, provided field conditions allow, soil temperatures are still suitable for Atlantis (mesosulfuron + iodosulfuron) application in wheat when blackgrass has 2-3 leaves. It is a good opportunity to also apply an insecticide for aphid/barley yellow dwarf virus control. Aphids can be found in crops now and a few frosts will do them no harm.

Remember also to check for aphids in crops that aren’t going to receive a post-emergence herbicide, typically those with only meadowgrass and broadleaved weeds. It is easy to ignore those fields and shut the gate after the pre-emergence treatment, there being a natural reluctance to go through with an aphicide only.

Grass weeds in winter oats need treating as soon as possible once the crop has two leaves, again including an aphicide if necessary.

Most oilseed rape has now been treated for phoma, though it took some time to develop in the more resistant varieties. Keep checking for re-infection and fresh lesions, as a second treatment may be needed before Christmas, especially if we have mild, wet weather. Small plants are at greater risk than big, well established ones.

Blackgrass in rape has not been well controlled by contact graminicides and we are now reliant on propyzamide to do the job. We need the soil temperature below 10C for propyzamide application and at the end of last week it was down to 8C, albeit at 700 feet up on the Cotswolds.

There is mildew in some winter barley crops. Mostly this is where the crop is thick and well-tillered and treatment is unlikely to be worthwhile. If however a crop is poorly-established and on light soil a mildewicide should be considered, as mildew will affect root development.

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