France

One of the most extensive monitoring approaches is being conducted in France to survey the bee safety of the thiamethoxam seed treatment in maize. The implemented survey is aimed at evaluating the potential side-effects of the use of coated seeds on pollinating insects, and more particularly on the honey bee. This survey was implemented over 3 years, covered 3 to 6 regions and involved several monitoring sites for each region. Sites had intensive maize cultivation grown from either treated or non-treated maize seeds. Apiaries were settled before sowing and remained until overwintering. Final data indicated a very low exposure of bees to residues of thiamethoxam over the entire growth period, and highlighted no product-related effect on colonies, even after several years of cohabitation.

Germany

A more small-scale approach with a similar use scenario of a neonicotinoid seed treatment product was conducted in 2008/09 by the University of Hohenheim in Southwestern Germany. Bee hives set up at different locations in a maize growing region where the crop was seed-treated with clothianidin were monitored during a season until the following spring; observations were accompanied by extensive residue sampling. No adverse effects of the treatment were found (Liebig et al., 2008; Liebig, 2009). Other small-scale monitoring projects with a very specific focus have been conducted by the German Bee Institutes in 2010, to assess the potential effects of soil- and seed-applied neonicotinoid products (thiamethoxam, clothianidin) in maize and in other crops on exposed honey bee colonies. Although individual exposed bee hives displayed more or less pronounced mortality peaks on single days, no adverse effects on the colony level were observed.

Italy

Further activities to monitor potential effects of neonicotinioid seed treatment, particularly in maize, to honey bees, are being conducted in the framework of the ApeNet Monitoring in Italy. Latest results are reported by CRA-API (2009, 2010). The report does not refer to significant issues related to pathogens, but describes a couple of cases of acute poisoning by pesticides, most of them probably caused by incorrect applications. Moreover, mechanistic studies on pesticide exposure and intrinsic pesticide effects to bees are reported which are, however, strictly seen not a part of monitoring activities. In the previous reports (CRA-API, 2009, 2010) other useful data are reviewed based on descriptive monofactorial analysis of the potential risk and data monitoring in field. Mitigation are proposed. The project is ongoing and worth results are foreseen encompassing novel assessment of the health of the colonies by means of biomarkers and biochemical approaches.

Austria

Another monitoring project with focus on neonicotinoid seed treatment products is the MELISSA Project in Austria. In this project, particular attention is directed to the investigation of any damage to bees that is reported in association of growing maize. (Latest report: Girsch and Moosbeckhofer, 2011). According to preliminary results, the safety of neonicotinoid seed treatment products to honey bees can be sufficiently ensured when the prescribed security measures for the use of these products are complied with.

Switzerland

A monitoring project that consisted of a series of field studies was conducted in 2009 by the Swiss authorities, to investigate potential effects of a neonicotinoid seed treatment in maize due to dust during drilling, and due to guttation liquid, on exposed honey bee colonies (Bundesamt für Landwirtschaft, 2009). No increased mortalities or other adverse effects of the treatment were seen, either during sowing of the crop, which was conducted in compliance with the prescribed safety measures, or during the guttation phase of the crop.

Belgium

A monitoring of effects of Imidacloprid seed-treated maize to exposed bee colonies was conducted in Belgium by Nguyen et al. (2009). Sixteen apiaries located in the vicinity of treated or untreated fields were surveyed over one year. No adverse effects of the treatment could be found. The results indicated a significant correlation between the number of colonies per apiary and the mortality rates in the respective apiary. However, the mortality rate was inversely correlated with the surface of maize fields treated with Imidacloprid in the surroundings of the apiary, suggesting that the pesticide treatment did not interfere with bees’ condition.

* * *

So far, none of the pesticide-related bee monitoring approaches found a clear connection between bee colony mortality as a general phenomenon and the exposure of bees to pesticides. However, regionally limited bee issues with pesticides that were mostly related to specific local conditions and/ or an inappropriate application of the respective product could be detected by monitoring approaches, whereby the underlying problem could later on be resolved by appropriate mitigation or stewardship measures.

Bee health in Europe - Facts & figures
Compendium of the latest information on bee health in Europe
http://www.pollinator.org/PDFs/OPERAReport.pdf
 
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