DESPITE THE recent cold spell, 84% of UK weather stations have now had weather which suggests pollen beetle migration has started – including three in Scotland.

The beetles are important because they cause significant damage to oilseed rape crops before they flower. The three weather 'positive' stations in Scotland – at Haddington, Leuchars and Huntly – are part of five monitored in Scotland by Bayer for its Pollen Beetle Predictor. This means that beetle migration has been detected in 69 of 83 stations across the UK.

At present, migration across the UK is only partial, with beetle populations expected to increase in the coming weeks. However, forecasts suggest that temperatures will remain lower than the 15°C required for beetles to migrate to crops en masse, which puts crops at greater risk.

Rothamsted researcher, Dr Sam Cook, said the risk from pollen beetle this season could be greater due to a slow start in spring growth. Growers and agronomists should check the prediction tool to monitor for new migrations and the extent of that migration and assess the mean number of beetles per plant for comparison against threshold levels.

To access the predictor go to: https://cropscience.bayer.co.uk/tools-and-services/pollen-beetle-predictor/