May 172018

by Robert Arnason

Health Canada proposed last November to ban imidacloprid, an insecticide applied to fruit, vegetables, potatoes and many other crops across the country.

Twelve months have passed since the announcement, but Canadian farmers who use the insecticide will have to wait another year to know if it’s banned or not.

“Health Canada is reviewing an extensive amount of data and information, including recently submitted water monitoring data,” a Health Canada spokesperson said.

“Once this information is reviewed, the proposed decisions will be subject to a public consultation period and final decisions are anticipated by December 2018.”

Health Canada’s Pest Management Regulatory Agency has proposed phasing out agricultural and outdoor uses of imidacloprid over three to five years. The PMRA said the phase-out is necessary because the insecticide was accumulating in water near agricultural land.

The concentrations in water were reportedly putting aquatic insects at risk and threatening animals that rely on those insects for food.

The mode of action of imidacloprid is similar to two other neonicotindoids: clothianidin and thiamethoxam. Those products are used as a seed treatment on nearly every canola and corn crop grown in North America and a portion of the soy crop.

PMRA scientists are also reviewing those insecticides to determine if they threaten aquatic life.

A number of agricultural groups have said banning imidacloprid is an extreme response because other policies could limit the use of the insecticide and reduce the threat to aquatic insects.

Many growers depend on the Bayer product for insect control. Fruit, vegetable and potato producers are the main users of imidacloprid, but prairie growers use it on wheat crops to control wireworm.

The PMRA is going slow with its decision on imidacloprid, which gives scientists time to publish new research on the insecticide.

In November, toxicologists at the University of Saskatchewan released a paper on imidacloprid and songbirds in Scientific Reports.

The scientists fed canola seed coated with imidacloprid to white-crowned sparrows. They observed detrimental effects in birds that consumed only four canola seeds.

“These chemicals are having a strong impact on songbirds,” said Margaret Eng, a post-doctoral researcher who led the U of S study.

“We are seeing significant weight loss and the birds’ migratory orientation being significantly altered.”

The toxicologists said exposure to imidacloprid could compromise the health of songbirds and their ability to reproduce.

A spokesperson for Bayer said the study is misleading because it doesn’t represent real world conditions for white-crowned sparrows.

“The repellent properties of the (insecticide) seed treatment would normally deter birds from ingesting whole canola seeds treated with imidacloprid,” said Paul Thiel, vice-president of product development and regulatory science for the crop science division of Bayer in Canada.

“Previous studies of caged birds indicated a lack of interest in imidacloprid treated seed if other food sources were available.”

Thiel said imidacloprid is rarely used as a seed treatment for canola, reducing the chance of birds eating such seeds.

A Health Canada spokesperson said PMRA scientists are considering the U of S study.

“It is too early to tell what impact it may have on the final decision.”

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