Canola seed coated with neonicotinoid insecticides marked a major advance for producers, providing good control of pests, such as flea beetles, while allowing much-reduced levels of insecticide.
“If you look at reverting back to foliar insecticides and needing three to four applications to match what a seed treatment would do, you can start having some serious impact on non-target insects,” said Curtis Rempel, vice-president of crop production and innovation with the Canola Council of Canada.
Rempel was one of five presenters during a session on neonics at the annual Canola Industry Meeting and Canola Innovation Day held early last month by Ag-West Bio in Saskatoon.
The event drew about 280 attendees representing researchers, plant breeders, seed growers and producer groups.
The honeybee has become the poster child in the neonic saga, but Elomir Simko points out a paradox: neonic seed treatments are supposed to be bad for bees, but Saskatchewan bees in the heart of canola country have never had it better. The veterinary pathologist from the Western College of Veterinary Medicine said there is much disagreement among the literature and in his own work.
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“There is a discrepancy between our study and these (others),” he said. “Based on these, at least 50 percent of our bees’ hives should underperform. Unfortunately, we are the record-producing province for honey per hive.”
Simko pointed out there is little research capacity in bee health in Canada, unlike Europe where bees are considered domestic livestock and the subject is often taught in veterinary colleges. He urged the canola and beekeeping industries to fund a dedicated research chair in the area.
Dispute over the effects of neonics also extends to aquatic insects and birds.
Christy Morrissey, an avian and aquatic ecotoxicologist with the School of Environment and Sustainability at the University of Saskatchewan, presented data from her team’s research that shows clear harm to both.
Saskatchewan and Manitoba are blessed with abundant wetlands, but this makes them particularly vulnerable, she said. Neonics readily dissolve in water and don’t break down easily in the environment. There, they have an adverse effect on aquatic insects, such as reducing reproduction and therefore populations.
Farmland birds are particularly vulnerable, Morrissey said, because many eat insects and some, such as swallows, eat virtually nothing else.
Morrissey said birds also come into contact directly with neonics, explaining her team has observed them eating treated seeds from spills on the ground that haven’t been cleaned up, as well as scratching the soil to get at seeds that have been sown in the field.
While a typical bird might need to eat about three dozen seeds for a lethal dose, she said ingesting just a few will cause them to rapidly lose weight and stop eating.
Morrissey is also looking for farmers to partner with in future research looking at mitigation measures, such as wider buffer zones between crops and water bodies, and intercropping options to reduce the need for the insecticides altogether.
Claudia Sheedy, a researcher with Agriculture Canada in Lethbridge, said neonic residues can be found in rivers, streams, wetlands — even in high mountain glaciers, where they have blown in from thousands of kilometres away in southeastern Asia.
Sheedy worked with Alberta Agriculture and the Saskatchewan Water Security Agency to look for neonic residues, particularly in streams and rivers. She found that thiamethoxam, the most commonly used neonic, showed up at higher detection levels in April and May, with an unexplained spike in July. Data for clothianidin and imidacloprid were similar.
“By August and September, we don’t see neonics in water across the Prairies,” she said, adding there was no clear pattern.
In Alberta wetlands, for example, her team found few residues.
“You don’t see neonics a whole lot in Albertan wetlands for some reason,” she said. “We actually selected wetlands for the study that were in canola production areas, and yet we didn’t see a whole lot of them.”
Rempel said that no neonics were detected in the nearly 3,300 samples collected in 2018 from 315 sites across Canada, analyzed in the labs of Sheedy and others, with equipment capable of detecting 10 parts per trillion.
“The bottom line is that there were a lot of water samples generated over the last number of years and submitted to PMRA (Pest Management Regulatory Agency) so they can make a more informed risk assessment and a more informed decision,” Rempel said.
According to its website, Health Canada is evaluating potential risks to aquatic insects from neonics and is expecting to report on its findings soon.