West: Weed control and early fungicides

Good weather at last and a huge amount of spraying, top-dressing and drilling has taken place in the last few days, though some fields are still too wet to travel.

The majority of winter oilseed rape crops are coming up to green bud stage and will soon need a growth regulating fungicide. Low levels of light leaf spot can be found in some. At green bud look out for pollen beetles, but only spray if the threshold of 15 per plant is exceeded.

Cereal growth has been 10-14 days behind normal but crops will now respond to day length, moving through the growth stages more rapidly to catch up with normal development. This will lead to a “compressed” season for fungicide use and a temptation to miss out the T0 treatment.

In winter barley rhynchosporium is the main concern with net blotch also found in some crops. It is better to apply a fungicide at stem extension rather than waiting for GS 31; once rhynchosporium is established it is much harder to control. Growth regulators can be applied at the same time, usually a Moddus (trinexapac-ethyl) and chlormequat mix.

Septoria is present in all wheat crops, with eyespot in some and the
potential for rust always to be borne in mind. Many T0 treatments have
been applied in the past few days and it is still worthwhile especially
in the more backward crops. T1 fungicides probably won’t be applied
until April 20th-25th and an earlier low dose gives disease suppression
and peace of mind should the conditions be unsuitable later in the

As spring barley emerges so does the blackgrass. Axial is probably
the best option for treatment, applied at the two leaf stage of the
weed. Don’t expect total control.

Look for weevil attacking spring beans as they emerge. Spray if lots
of notching can be found on the leaf margins.


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