Take-all red alert
Take-all red alert
MONSANTO has issued a take-all "red alert" to wheat growers after finding worrying levels of the disease in crops.
"We even diagnosed take-all in the roots of a number of crops well before Christmas, which is almost unprecedented," says Monsanto technical specialist, David Leaper.
IACR Rothamsteds Richard Gutteridge also fears severe disease pressure. "My gut feeling is that it will be a bad year. But much depends on the weather from now on."
He has not surveyed any crops yet, but a bioassay of soils last August, which indicates the take-all infectivity of the soil, showed 40% of roots were infected.
That is a worryingly high figure, he says. Whether it translates into plants infected this spring depends on sowing date and winter disease progress.
His advice for infected crops is to keep them stress-free. "Split your nitrogen, perhaps into three doses. Keep the leaves free of disease – if you are using Amistar (azoxystrobin) you may find this has a beneficial effect."
Early sowing and a large area coming out of set-aside are partly to blame to for the take-all upsurge. "But warm and moist soil conditions right through to the end of November have been the main culprits," says Mr Leaper. *