A study from the University of Guelph (U of G) shows exposure to pesticides may be negatively affecting bumblebees' ability to forage wildflowers.

According to the research, bumblebees exposed to realistic levels of pesticides can take longer to extract pollen and seem to pick flowers with less sugar.

Nigel Raine, the Rebanks Family Chair in Pollinator Conservation at U of G and senior author of the study, says his findings are a concern for pollinator-dependent crops, but also for the wider ecosystem services pollinators provide. Raine thinks this is part of a wider conversation on pesticide use.

"Clearly pesticides are designed for a useful job in mind to control pest insects — and they have a great role to play there — but it's when the usage of those pesticides has unintended consequences on beneficial insects like pollinators," Raine says. "And that might be about the timing of use, how much is being used, and how widely they're being used — particularly there's been a lot of conversation with neonicotinoid seed treatments where the levels of usage are quite high."

When it comes to use of neonicotinoids specifically, Manitoba Agriculture provincial entomologist John Gavloski also says neonics are being overused, partly because the seed treatment is often marketed as a growth-enhancer for crops in stressful conditions.

However, he explains the main purpose of neonics is specific, mainly to address problems with an insect called wireworm.

"Wireworms, they're in the soil, they don't come above the ground so you can't get them with a foliar insecticide. Really the only way to manage them is with seed treatments, hence the neonicotinoids," Gavloski says, although he adds wireworms are not a widespread chronic pest in Manitoba.

While Ontario has legislation that restricts producers from using neonics unless land is surveyed to confirm a pest problem, Manitoba does not have such protocol. Gavloski says it's tricky because Manitoba doesn't have good economic thresholds for wireworms, and they're a pest that's very hard to monitor and sample for.

"It's a very complicated thing," he says, "so it's controversial."

Raine thinks whether it comes to neonicotinoid seed treatments or other types of pesticides, we need to be thinking critically about how we use the pest-management tools.

"We need to be careful that we're getting the balance between the protective value where we need it against those damaging pest, (compared to) the potential later consequences for beneficial insects like pollinators," he says.

Raine says as a whole, it's important to support pollinator health to support crops and agriculture.