Interim Conclusions Based on Two Years of Honey Bee Mortalities
Following the evaluation of the 2012 honey bee mortalities it was concluded that the planting of corn seeds treated with the nitro-guanidine insecticides clothianidin and/or thiamethoxam contributed to the majority of the bee mortalities that occurred in the corn growing regions of Ontario and Quebec. The likely route of exposure was insecticide contaminated dust generated during the planting of treated corn seed. The unusual weather conditions were thought to have been a contributing factor.
Based on the detailed analysis that has been completed for the 2012 honey bee mortalities and the information available (as of September 26, 2013) for the 2013 mortalities there are similarities in the information reported. The mortalities occurred in the same areas and most coincided with the start of corn planting. Levels of residues detected in samples collected in 2013 were similar to levels found in 2012.There was an increase in the number of reports received by Health Canada in 2013, however, it is not clear if this was due to an increase in incidents or an increase in reporting since Health Canada actively promoted the channels to report honey bee mortality after the experience of 2012.
Preliminary information indicates that there may be differences in the information reported for the 2013 incidents which included losses of field force; steady decline in population; and more reports of lack of recovery and chronic or on-going effects such as queen and brood effects.
The information evaluated to date, suggest that clothianidin and/or thiamethoxam contributed to many of the 2013 bee losses. However, there is sufficient information to indicate that at least four of the bee mortality incidents that were reported to the PMRA are not related to neonicotinoids. Evidence exists that some of the four were related to pests and diseases, while others were related to spray events. Additional information continues to be collected for consideration in the PMRA’s evaluation.
Conclusions from the 2012 honey bee mortalities suggested that the unusual weather patterns during that spring were a contributing factor; however, in 2013 with more typical weather patterns the PMRA continued to receive a significant number of pollinator mortality reports. Consequently, the PMRA has concluded that current agricultural practices related to the use of neonicotinoid treated corn and soybean seed are not sustainable. The PMRA intends to implement additional protective measures for corn and soybean production, and issued a Notice of Intent on September 13, 2013 outlining action to protect bees from exposure to neonicotinoid pesticides with a closing date for public comment of December 12, 2013.
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