European Commission plans to limit farmers’ use of three common neonicotinoid insecticides over concerns for bees are under the spotlight again this week, as a study published by the UK Department for Environment, Food & Rural Affairs (DEFRA)* concludes that their risk to bee populations is low.
The 76-page report entitled ‘Effects of neonicotinoids seed treatments on bumble bee colonies under field conditions’ underlines that its findings “did not show that neonicotinoids used within a normal agricultural setting have a major effect on bumble bee colonies”. The study established 20 colonies & examined their development at 3 different sites in the vicinity of oilseed rape that was grown from a) untreated seeds or from seeds treated with the insecticide b) clothianidin & c) imidacloprid. Authors of the report outline that “systematic differences in the pesticide residues were found across the three sites, but these were not related to the treatment applied to the adjacent crop”, suggesting bumble bees travel long distances to forage for nectar & pollen. Colonies at each of the 3 sites grew & survived until the end of the experiment & the number of new queens produced in the colonies “was not significantly different across the 3 sites”, the report adds. Conducted by the Food & Environment Research Agency, the study acknowledges that this was “not a formal statistical test of the hypothesis that neonicotinoid insecticides reduce the health of bumble bee colonies”, but notes an absence of a “clear relationship between observed neonicotinoid levels & measures of colony success”. In a nod to the European Commission, it underlines the “importance of taking care in extrapolating laboratory toxicology studies to the field”, calling for further studies to be conducted under natural conditions. In a 9-page assessment accompanying the report, DEFRA outlines that “laboratory based studies demonstrating sub-lethal effects on bees from neonicotinoids did not replicate realistic conditions, but extreme scenarios”. The UK Department continues its work on research to better understand what levels of pesticide residues & disease in honey bees are considered “normal” & has commissioned a longer-term analysis seeking to quantify the actual exposure of wild bumblebees to sub-lethal doses of neonicotinoid insecticides across the UK. In a statement issued this week, it calls on the Commission “to complete its scientific assessment, taking account of the UK’s new research & to assess the impacts of action so that the measures proposed are proportionate to the risks identified”.
DG SANCO officials take note of the report, but add that EFSA’s opinion provided the Commission with “solid scientific ground to move forward with its proposal in the coming weeks”. Speaking on behalf of the UK National Farmers’ Union, Dr. Chris Hartfield, an expert on bee health, said the DEFRA study shows that “we do not have an adequate understanding of the levels of exposure to neonicotinoids experienced by bees under
field conditions”. Without this “fundamental” piece of information, it is not possible to determine whether & how harmful the impacts are to bees under field conditions. Following the inconclusive vote at last month’s Standing Committee on proposals to restrict the farm use of pesticides containing clothianidin, thiamethoxam or imidacloprid to non-flowering crops & winter cereals from July 1 for 2 years [see AF21-13] – the UK abstained - a second vote at the Appeals Committee is expected to take place in the second half of April.
*For more see http://www.defra.gov.uk/environment/quality/chemicals/pesticides/insecticides-bees/