HGCA recently published a ‘snapshot survey’ showing 17,000 hectares of winter oilseed rape had been lost to flea beetle damage up to the end of September, in the first autumn without access to the important pesticides.
While this only equated to just over 3 per cent of the winter OSR crop, this masked significant regional variations, with losses estimated at in excess of 40 per cent in some southern and eastern counties.
NFU combinable crops board chairman Mike Hambly urged winter oilseed rape growers to remain vigilant.
“Bearing in mind loss and damage figures already recorded, HGCA identifies that well over 40 per cent of the UK rapeseed crop was still at a particularly vulnerable stage to damage from cabbage stem flea beetle at the end of September,” he said.
“Anecdotal evidence received from farmers in certain areas of the country show significant losses in the oilseed rape crop, with the worst hit being in the Eastern and South East regions – among the most productive arable areas of the country, producing almost 40 per cent of English rapeseed last year.”
He described OSR as an ‘incredibly important crop for the economy and for biodiversity on farms’ the third most commonly planted crop in England and an abundant source of early nectar and pollen for bees.
“But with a key element of crop protection being withdrawn for 2014, and with 60,000 tonnes of rapeseed that now won’t be harvested in 2015, farmers will take a careful view on the risk of growing as much of the crop in future without adequate insect pest control,” Mr Hambly warned.
He also highlighted the ‘worrying’ increase in levels of cabbage stem flea beetle resistance to pyretheroids, the crop spray that has generally seen as the most credible alternative to the neonicotinoid seed treatments.
Research at the Rothamsted has shown shown up to 60 per cent resistance in what Mr Hambly said ‘had been growers only hope of saving their crops where high beetle numbers were causing damage’.
“While the 120 day emergency authorisation of an additional insecticide will help a little now, from 2015 onwards there will be no reliable protection available,” he added.
“The NFU continues to call on policy-makers to urgently consider and review the emerging evidence showing the damaging effects of continued restrictions of crop plant protection.
“Farmers need all of the tools available to keep up with our growing demand for food.”