PMRA reviews insecticide link to bee deaths

A class of insecticides that could be banned in the European Union because of their risk to honeybees is also under review in Canada.

The neonicotinoid class includes imidacloprid, clothianidin and thiamethoxam products which are the basis for several popular insecticides and seed treatments in Canada. Imidacloprid products include Bayer’s Admire and Gaucho, and thiamethoxam is contained in Syngenta’s Cruiser products. Clothianidin is part of Bayer’s Prosper seed treatment.

On June 12, 2012, the Pest Management Review Agency issued a notice that nitro-guanidine neonicotinoids were under re-evaluation for potential effects on pollinators “in light of changes in the information required and global updates to the pollinator risk-assessment framework.”

The review was apparently in response to an unusually high number of honeybee-mortality reports last spring from beekeepers in corn-growing regions of Ontario, involving over 40 beekeepers and 240 different bee yard locations. One report was received from Quebec involving eight bee yards.

A Health Canada report says, “The information evaluated suggests that 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 corn-growing regions of Ontario and Quebec in spring 2012. The likely route of exposure was insecticide-contaminated dust generated during the planting of treated corn seed. The unusual weather conditions in the spring of 2012 were likely also a contributing factor.”

Dry weather during seeding in 2012 apparently contributed to a higher-than-normal shedding of dust from treated seed.

On Feb. 4, 2013 Health Canada released a document advising of best management practices for handling treated seed.

“While the focus of this document is on nitro-guanidine neonicotinoid-treated corn seed, these measures may be extended to other types of treated seed or to other insecticides if a scientific evaluation shows that dust during planting poses a concern.”

EU ban possible

EU governments failed to agree on a ban on the products at a meeting Mar. 15, but the European Commission could force one through by the summer unless member states agree on a compromise.

Under EU rules, member states now have two months to reach a compromise or the commission will be free to adopt the proposal.

“Forcing through the ban is one of the options available to us but first we need to reflect politically on the best way to proceed,” said EU health spokesman Frederic Vincent.

The commission, which could also try to get a majority for a compromise proposal, put forward the restrictions in January after the EU’s food safety watchdog EFSA said neonicotinoids posed an acute risk to honeybee health.

The proposal would ban neonicotinoids on all crops except winter cereals and plants not attractive to bees, such as sugar beets. It would apply from July 1, 2013, ensuring this spring’s maize sowing is unaffected, with a review after two years.

A Syngenta- and Bayer-funded study showed a blanket ban on treating seeds with neonicotinoids would cut EU net wheat exports by 16 per cent and lead to a 57 per cent rise in maize imports, costing the EU economy 4.5 billion euros per year.

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