A new US bee study has highlighted the "diversity of ‘chemical cocktails’ bees are ingesting" say its backers.
The new research suggests some pesticides at field realistic doses affect honey bees by doubling or even tripling their susceptibility to disease.
The paper, Crop Pollination Exposes Honey Bees to Pesticides Which Alters Their Susceptibility to the Gut Pathogen Nosema ceranae has been written by Jeffery S. Pettis of the Bee Research Laboratory USDA-ARS, Elinor M. Lichtenberg Department of Entomology University of Maryland, Michael Andree of University of California, Jennie Stitzinger of USDA-APHIS, Robyn Rose and Dennis van Engelsdorp.
Their study found nine different pesticides in pollen.
Soil Association policy head Emma Hockridge said: "This is an extremely worrying finding which should raise alarm bells – the study demonstrated that we may be massively underestimating the impacts of pesticides on our pollinators.
"Whilst the US study found on average nine different pesticides in pollen, in the UK an average of 20 different pesticides are applied to fruit, 12 to vegetables and 16 to arable crops," she added.
"For strawberries, the average number of different pesticides used last year was nearly 30. This means bees are likely to be coming into regular contact with mixtures of pesticides with combined effects potentially much worse than previously thought."
Research reported by HW last week from the US found neonicotinoids in garden plants at retailers.