Bumble Bee Study Does Not Affect Neonicotinoid Conclusions, EFSA Says

5 June 2013 --- EFSA has identified several weaknesses in a study, published by the UK Food and Environment Research Agency (FERA), which suggested that neonicotinoid pesticides do not have a major effect on bumble bee colonies under field conditions.

Given these weaknesses, the Authority considers that the study does not affect the conclusions reached by EFSA regarding risks for bees related to the use of the neonicotinoid pesticides thiamethoxam, clothianidin and imidacloprid, published in January 2013.

The Authority made the following points regarding the relevance of the study, Effects of neonicotinoid seed treatments on bumble bee colonies under field conditions (Thompson et al.), to the risk assessments published by EFSA:
•EFSA’s assessments covered the authorised uses of a number of plant protection products containing thiamethoxam, clothianidin and imidacloprid across the European Union. The FERA study looked at only one crop – oilseed rape – and two plant protection products – one containing clothianidin, the other imidacloprid – authorised for use in the UK. Furthermore, the test sites and surrounding areas used in the FERA study reflect a small sample of agricultural conditions in the UK and cannot be considered representative of conditions in other parts of the EU.
•Two important routes of exposure – dust and guttation – were not addressed by the FERA study.
•In its assessments, EFSA reached conclusions mainly for honey bees, and identified a data gap for other pollinators. Field studies of bumble bees cannot be used to understand the risks to honey bees and other pollinators because of significant species differences.

EFSA’s experts highlighted a number of other deficiencies in the report. These include:
•Inconsistencies and contradictory statements regarding the objectives of the study.
•Absence of suitable control bee colonies. In particular, analysis of residues in pollen and nectar showed that the “control” site had been contaminated by thiamethoxam.
•Environmental conditions were varied across the three the test sites, which reduces the sensitivity of the study in detecting effects on colonies.

EFSA also raised concerns about how Thompson et al. elaborated and interpreted the study results to reach their conclusions.