Bayer CropScience Responds to Forbes Bee Article

Thursday, May 3, 2012
Bee Health

Bayer CropScience responds to recent criticism on Forbes.com: As an environmental toxicologist with 25 years of experience – and current employee of Bayer CropScience – I feel it is important to share a different perspective on bee health and Colony Collapse Disorder (CCD) with you and your readers. You state that “despite a lot of research since CCD was first recognized in 2006 the causative factors have not been identified.” However, it is important to note that CCD is a symptom, not a disease. Just as a fever is symptomatic of a many different illnesses in humans, the rapid disappearance from colonies of worker honeybees (i.e. CCD) appears to be a symptom that can occur during the end-stages of multiple bee diseases. What is clear is that the occurrence of CCD, and honeybee colony losses in general, are not correlated with exposure levels to agrochemicals (van Englesdorp et al. 2009). CCD has been reported from organic beekeeping operations and in locations far away from agricultural lands. It is also important to understand that CCD is a newly coined term for a symptomology that has been observed by beekeepers for more than 100 years. In their descriptive study of CCD, van Englesdorp et al. stated “since 1869, there have been at least 18 discrete episodes of unusually high colony mortality documented internationally. In some cases, the descriptions of colony losses were similar to those described above.” The idea that it all started in 2006 and coincided with the introduction of neonicotinoid insecticides is a myth. Interestingly, there does seem to be a correlation between recent occurrence of CCD and the presence of residues of Varroa control chemicals. In these situations, hives with lower rates of CCD generally have higher varroacide residue levels. This suggests that beekeepers who are more vigilant in controlling Varroa are less likely to have CCD in their colonies. Varroa mites weaken bees’ immune systems and are themselves vectors of pathogens that may cause severe sickness in bees and trigger the CCD response. While I believe existing data suggest this hypothesis is true, more experiments need to be run in order to definitively test it. Ultimately, there is no credible scientific evidence demonstrating a link between the use of neonicotinoid insecticides and the occurrence of widespread honey bee colony losses, including CCD. Imidacloprid, and neonicotinoid insecticides generally, remain safe and effective management tools to control a wide range of destructive insect pests. There have been a few incidents of acute poisoning of honey bees from the use of neonicotinoids, though far fewer compared to other major classes of insecticides. Still, in these cases, the affected colony typically recovers to normal health and population levels within a few weeks. It is not just my opinion that neonicotioinds are generally safe for bees, when used properly. This has been the conclusion of many recent peer-reviewed scientific publications where the authors have either reviewed all of the pertinent evidence (see, for example, Cresswell et al. 2011) or conducted multifactorial studies of bee health in various regions of the world (see, for example, Chauzat et al., 2009; Nguyen et al., 2009; Generisch et al., 2010; van Englesdorp et al., 2009, 2010). This is also the conclusion of the EPA, whose position is based on their review of hundreds of research studies conducted by independent researchers as well as chemical manufacturers. Bayer has been actively involved in finding solutions to improve bee health for more than 25 years. As a company, we also are committed to environmental stewardship and sustainable agricultural practices, including the conservation of beneficial insects such as honey bees. David L. Fischer, Ph.D. Director, Environmental Toxicology and Risk Assessment Bayer CropScience LP Research Triangle Park, North Carolina Literature cited: Blacquière T, Smagghe G, van Gestel CA, Mommaerts V. Ecotoxicology. 2012 Feb 18. [Epub ahead of print] Neonicotinoids in bees: a review on concentrations, side-effects and risk assessment. Plant Research International, Wageningen University & Research, PO Box 69, 6700 AB, Wageningen, The Netherlands resswell, J.E. et al. (2012): Dietary traces of Neonicotinoid pesticides as a cause of population declines in honey bees: an evaluation by Hill’s epidemiological criteria. – Pest Management Science: doi: 10.1002/ps.3290. Chauzat M-P., et al. (2009): Influence of Pesticide Residues on Honey Bee (Hymenoptera: Apidae) Colony Health in France. Environ. Entomol. 38(3): 514-523 (2009) Genersch E, et al. (2010): The German bee monitoring project: a long term study to understand periodically high winter losses of honey bee colonies. Apidologie 41 (2010) 332–352 Nguyen, B.K., et al. (2009): Does Imidacloprid Seed-Treated Maize Have an Impact on Honey Bee Mortality? J. Econ. Entomol. 102(2): 616-623. van Engelsdorp D., et al. (2009): Colony Collapse Disorder: A Descriptive Study. PLoS ONE 4(8): e6481. van Englesdorp D., et al. (2010): Weighing Risk Factors Associated with Bee Colony Collapse Disorder by Classification and Regression Tree Analysis. J Econ Entomology 103(5):1517-1523.

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