A high level of concern was raised last spring regarding bee kills and corn planting. Many growers are asking what actions they can take to help reduce the risk of bee kills this spring during planting. We will try to clarify the situation, and give the best recommendations we can provide at this time. In the spring of 2012, coinciding with corn planting, there were approximately 200 incidences of what was likely acute poisoning of honey bees in Ontario. Representatives from the Ministry of Environment (MOE), Pest Management Regulatory Agency (PMRA), and OMAFRA investigated affected bee hives, taking bee samples for residue analysis by PMRA. Though final results have not been released, PMRA's initial lab results indicate "that pesticides used on treated corn seeds may have contributed to at least some of the 2012 spring bee losses that occurred in Ontario, however, there is still additional information being collected". It is important to note that they have found no cases of off-label use by growers. It is also important to note that, though the analysis indicates the presence of clothianidin (active ingredi- ent in Poncho), thiamethoxam (active ingredient in Cruiser) breaks down to metabolites that include clothianidin. Virtually all corn seed sold in Ontario is treated with some form of the insecticides in question. The cases in 2012 were likely acute poisonings where bees were killed from short term exposure to lethal doses of an insecticide.
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