Light leaf spot infections have been identified in oilseed rape crops across the UK – indicating that growers should remain vigilant for disease onset this winter and consider a fungicide spray before Christmas.
An increasing number of leaf samples have tested positive for light leaf spot since Bayer’s SpotCheck service re-opened for submissions from farmers and agronomists in October.
By 9 November, 50 out of 102 samples had revealed 10% incidence of light leaf spot or more, after three days of incubation. Of these, 19 samples showed 50% disease incidence or more.
Positive samples were received from a wide geographic area. They included samples from Lincolnshire, Norfolk, Suffolk, Cambridgeshire and Kent – as well as further West from Somerset and Wiltshire, Scotland and the north of England.
Bayer commercial technical manager Ella Crawford said: “Light leaf spot infections in early November in crops in East Anglia, the south coast and the west of England are further evidence of the southerly march of this disease.”
Winter funcigide applications can protect lower crop canopies, and prevent disease spreading to the pods in the spring during stem extension. Fungicides only offer protectant activity, so timing sprays depends on catching the disease early.
“Where fungicides applications are being planned this side of Christmas, growers should consider using a product such as Proline which offers activity against light leaf spot as well as Phoma,” said Ms Crawford.