It is now looking highly likely that forward OSR crops will avoid pollen beetle damage this Spring.
Bayer Pollen Beetle Predictor is showing little migration has occurred over the last week. Weather stations where migration is the most advanced are at just 23% migration having edged up from 17% a week ago. With the ‘new migration’ map indicating migration not possible across most of the country and chilly weather forecast it’s unlikely migration will progress much this week.
Monday morning’s BBC Weather forecast says: “Spring is going to be taking a bit of a break this week. There is some chilly weather on the way with cold air sweeping in from the North West.” This is expected to bring wintry showers and even some snow while temperatures remain below 10°C i.e. well below the 15°C needed for pollen beetle migration. Temperatures may start to climb again by the weekend.
Rothamsted researcher Dr Sam Cook comments: “While temperatures forecast for the coming week are unlikely to see much progress in pollen beetle migration, OSR crops – which still put on noticeable growth at 5°C – will continue to grow. Forward crops now have first flowers visible and so, even with the cooler weather forecast for this week, should soon be past the damage susceptible stage.”
Last week the remaining five weather stations on the ‘migration start’ map turned red so Dr Cook says all attentions should now be on the ‘new migration’ map to spot when conditions return to being suitable for migration.