Switch can provide alternate sprays to maintain necessary intervals for effective disease control as carrot fungicide programmes frequently now continue into October in mild autumn conditions.
Crop consultant David Martin said that Switch can be integrated into the crop's fungicide programme, with initial applications targeted at the key Sclerotinia timing before canopy closure.
"With additional activity against Alternaria, powdery mildew and other foliar diseases, it offers a welcome alternative action, to alternate with strobilurin fungicides in the programme."
Strobilurin-based fungicides can only make up a maximum of half of any carrot fungicide programme.
Martin added that the seven-day harvest interval could prove useful for carrot growers looking to exploit marketing opportunities that may arise during the growing season, when crops treated with fungicides with a longer interval could not be lifted.
The SOLA permits up to three applications of Switch in a season.
Dr Peter Gladders of ADAS has advised that growers need to start carrot Sclerotinia programmes before the crop canopy closes over and the first leaves start to senesce, as early as mid-July in some areas.
Repeated applications may be necessary every seven to 10 days in high risk situations. "If Sclerotinia is allowed to get established under the thick matt of decaying vegetation, then it will be almost impossible to control."
ADAS trials have shown that, under high Sclerotinia disease pressure situations where nearly 40 per cent of the crop was affected, Switch applied at 0.8 L/ha achieved more than 90 per cent control. Under lower disease pressure it effectively eliminated disease, whilst around 10 per cent of the untreated crop was affected.
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