Pest control products are registered by Health Canada's Pest Management Regulatory Agency (PMRA) for use only if there is reasonable certainty that no harm to human health or the environment will result from exposure to, or use of, the product as directed on the label. The PMRA collects incident reporting data under the authority of the Pest Control Products Act. If a pesticide manufacturer receives information about an incident involving one of their products, they are required by law to submit that information to the PMRA. Members of the public may also submit information about an incident directly to Health Canada. It is important to note that the information presented in incident reports reflects the observations and opinion of the person reporting it, and does not include any assessment by Health Canada, nor does it confirm an association between the pesticide and the effects reported.
Health Canada considers the reported information to determine if there are potential health or environmental risks associated with a pesticide and, if necessary, takes corrective action. Such action could range from minor label changes to discontinuation of the product.
In May, 2010, a bee keeper observed "abnormally high bee mortality" in front of a group of 15-30 bee colonies located in St-Dominique, an agricultural area in the Montérégie region of Québec, which is located within the major corn growing regions of Canada. While the exact number of affected bees is not known, it is reported that "the cumulative mortality over time was important".
Dead bees from the site were collected by the bee keeper and analyzed by the Ministère de l'Agriculture, des Pêcheries et de l'Alimentation du Québec (MAPAQ) using a multiresidue method that can detect approximately 200 different pesticides. Residues of clothianidin were detected.
In accordance with the Incident Reporting Regulations classification system, this incident was classified as Environment Moderate. This incident report is posted on the PMRA electronic Public Registry on the Health Canada website.
It is unknown how the bees were exposed to clothianidin in this incident. However, residues of this compound found in dead bees collected at the time of the incident confirms that exposure occurred.
Clothianidin is conditionally registered in Canada for use as a seed treatment, foliar spray and in-furrow applications to control insects. Clothianidin is a systemic pesticide, which means that they are taken up by the plant's leaves or roots and transported throughout the plant. Clothianidin is highly toxic to honeybees through oral or contact exposure.
Possible exposure to bees could occur from contact or oral exposure to drift from foliar application, dust-off from treated seeds at planting, and oral uptake of residues that may be found in nectar, pollen and guttation droplets.
The PMRA concluded that it is highly probable that exposure to clothianidin caused the bee mortality in St-Dominique. Even though it is not clear how the bees were exposed to clothianidin in this incident, this conclusion is supported by the fact that clothianidin is known to be highly toxic to bees and was the only pesticide found in the dead bees.
The causality of this incident was assessed based on evaluated information present at the time of the review. The PMRA has concluded that no additional regulatory action is required by Health Canada at this time. Consideration was given to the fact that clothianidin is conditionally registered and that this incident would be considered during the conversion to full registration, along with other requested data. It should be noted that any additional information regarding this incident that is provided to the PMRA will be taken into consideration and may change this conclusion.
More information about the Pesticide Incident Reporting Program is available on Health Canada's website. Should you require further information please contact the Pesticide Incident Reporting Program.