There has been much discussion and speculation in recent years as to the safety of neonicotinoids for bees, but scientific evidence was not always in focus. At the Bee Health Forum in Madrid, Spain from November 7 to 8, scientific consideration was given to the topic of bee health, addressing for example, the important question whether neonicotionoids are harmful for honey bee colonies under realistic field conditions. This conference – titled “Effects Of Pesticide Use On The Development Of Bee Diseases – Analytical And Ecotoxicological Threats And Challenges” – was organized by the European Reference Laboratories for Pesticide Residues in Fruits and Vegetables (EURL-FV) and Spain’s lnstituto Nacional de lnvestigación y Tecnología Agraria y Alimentaria (INIA). As part of a Spanish multi-stakeholder collaborative project, international experts came together for this conference to determine the current bee health situation in Spain and to evaluate risk factors for honey bees and wild pollinators. The main objective of the conference was for experts in the field to share data and experiences regarding honey bee health, including an analysis of the available monitoring data. This was to identify relevant sources of pollinator stress and to outline future collaborative research in these areas.
The participants reached a consensus: multiple stressors influence bee health, including pests and diseases, lack of nutrition, extreme weather conditions as well as beekeeping and agricultural practices. Ranking the relevance of each factor caused some debate: “Focusing on the honey bee monitoring data presented, parasites and diseases of bees appeared to be particularly relevant stressors in Spain, even more when combined with residues of several varroacides. In comparison, the impact of pesticides used in agriculture appeared insignificant, except for rare incidents,” says Agustí Soler, Food Safety & Good Agricultural Practice Manager at Bayer Iberia, who attended the Bee Health Forum.
Bayer bee expert Janine Doering presented the main results of a large bee safety study in German oilseed rape fields.
Despite the forum’s consensus on these scientific findings, one participant from academia still blamed neonicotinoids for the decline in wild pollinators. “However, this person’s theory was not supported by any specific data. Instead, it was based mostly on general statements concerning hazardous properties of neonicotinoids,” says Soler.
It is often seen that public perception of the factors affecting bee health differs from that of bee researchers in the scientific community and their views are based on media opinions and emotion rather than research. This scenario had an impact in 2013, when the European Commission restricted the use of three neonicotinoid substances in certain crops. The action was based on political concerns amid public pressure, fueled by NGO activities rather than any proven bee safety concerns. The European Food Safety Authority (EFSA) analyzed the results of previously submitted registration trials, using new and extremely conservative criteria. For this reason, Bayer and many research partners are now re-testing the usage of neonicotinoids under realistic field conditions to provide more evidence of the safety of neonicotinoids for bees.
At the Forum, Bayer representative Janine Doering strongly challenged neonicotinoid criticism by presenting the results of a large-scale field trial conducted in oilseed rape in Germany, which studied the impact of clothianidin seed treatment in oilseed rape on honey bees, bumble bees and solitary bees. Doering explained that the study started in 2013 with sowing treated seeds. In the following spring, bees were intensively observed: the results showed that honey bees foraging in treated oilseed rape fields attained stable colony development and delivered good honey yields. Similar findings were observed with the other two bee species. “The abundant data generated in this study led to the conclusion that clothianidin seed treatment does not negatively affect the health status of the various pollinator species studied,” says Doering. According to her “for members of the public, it is difficult to understand the quality of the data generated and why different researchers come to different conclusions when investigating the same substances. The conference participants agreed that by strengthening dialog, experts can help the public understand the variability in testing methodologies and findings, and explain potential reasons for this.”
All in all, Doering had a positive feeling about participants’ acceptance of her presentation: ”Most of them appreciated the scientific quality of the study, as well as the usefulness of large-scale trials, conducted under realistic field conditions. Value was seen in a weight-of-evidence approach including all the available information and discussing the pros and cons of neonicotinoid applications.”
The Spanish Bee Health Forum demonstrated once again that scientific audiences require valid facts to support arguments in order to discuss bee health in an objective way. “There was one great outcome: the – almost – general consensus on the value of monitoring data to identify relevant stress sources for bees,” says Soler. “I believe better training of beekeepers could greatly alleviate colony losses. It could also, at the same time, return the bee health debate to where it should have largely remained: at a veterinary – and thus, scientific – level.”