Two-thirds of the 83 UK weather stations monitored by the Bayer Pollen Beetle Predictor have had weather conducive to suggest pollen beetle migration has started, albeit at very low levels. Migration predictions have been confirmed by pollen beetle catches in Wye, Kent, Starcross, Devon and Welywn, Hertfordshire.
The warmer weather towards the end of last week, before the return of the “Beast from the East” at the weekend, created for the first time, conditions where migration was possible across many areas of southern and central England. And while the return to wintery weather will have stopped any possible further migration over the weekend, forecast warmer weather for this week means growers should be alert to migration beginning in their area.
This year’s early spring weather is in contrast to last year when temperatures were reaching up to 15°C in early March. The recent freezing temperatures and snow cover across the country have knocked back the crop and contributed to a slow start to spring growth in oilseed rape.
Rothamsted researcher Dr Sam Cook says this means growers and agronomists should check the prediction tool now to see if their nearest weather station has turned red. “If so, it’s time to put yellow sticky traps out in fields to monitor local abundance and keep an eye on the ‘new migration’ map within the tool. This tells you when it’s time to get into crops and assess average numbers against threshold. It helps to focus monitoring effort to when it’s most needed and facilitate practical use of thresholds.”