By Connor Lynch
GUELPH — A pesticide-treated corn and soybean seed has been unfairly demonized by environmentalists armed with studies that don’t prove death to the honeybee. Nevertheless, neonicotinoids, or neonics, have been blamed for the collapse of bee populations the world-over, conjuring flashy headlines such as “Beepocalypse.”
A lawsuit highlights the injustice. Four environmentalist groups — The David Suzuki Foundation, Friends of the Earth Canada, Ontario Nature and the Wilderness Committee — are suing Health Canada over its conditional approval of two neonics.
Farmers Forum asked the four groups for studies that prove that neonics are harmful to honeybees. We received five studies and sent them to two scientists at the University of Guelph for review.
But would the five studies support the idea that neonics harm bees? It’d be a stretch, said Dr. Angela Gradish, of the school of environmental sciences at the University of Guelph. The studies are good in that they establish ways neonics could affect bees; not whether or not they actually do in the real world, she said
“When you look at honeybees, field studies in particular, we don’t see a lot of strong evidence that neonics are implicated in declines, or, they’re only part of the picture.” Gradish said, adding that she thinks the Ontario government probably leapt without looking, as far as bees are concerned, in restricting neonics.
Four of the five studies are laboratory studies, where bumblebees were exposed to neonics in the lab and then sent into a natural environment. In four of the studies, researchers exposed bumblebees to neonic levels equal to the highest exposures found in the field. In one study, the bees were continuously exposed to neonics for 15 days; hardly a likely scenario in the wild, Gradish said. Some scientists argue that the level of exposure in the four studies is unrealistic, she said.
In another study, the only effects on bumblebees were observed at the highest concentrations of neonics. “This type of lab exposure is, most likely, an overexposure.” Apart from that, Gradish said “everyone’s agreed that (neonics) would not kill (bees) outright.”
Another relevant factor is that most of the concern in Ontario has focused on honeybees. Four of the five studies focused on bumblebees. Bumblebees and honeybees, however similar they may appear, are in fact two very different species, especially when it comes to their susceptibility to pesticides, said Gradish. Data on one of them can’t be used to make conclusions about the other, she said.
The next step to figure out what is really happening in the field is to get out there and do field studies. The five studies cited by the environmental groups are well and good in that they establish that neonicotinoids could kill bees. But whether or not they actually do in the field is another question entirely. This has been a major criticism from groups like the Grain Farmers of Ontario. You feed too much of one thing to a guinea pig and you’ll kill it. For instance, if a person were fed 11 cups of sugar just to see what would happen, that person would be dead. But no one is about to ban sugar.
Field studies since have been done, said Gradish. She’s aware of 15, all of which she’s reviewed. “There was virtually no effect (on bees) across all those studies.” Most of those studies were on honeybees, though there were a few, relatively inconclusive ones on bumblebees. “The overall effect, for each study, was there was no appreciable effect (on bees),” Gradish said.
One of the studies cited by the environmental organizations was a field study, done on a number of bee species, including bumblebees and honeybees. But the neonic-application rates it used are European, which are more than double typical rates in North America; studied plants were planted in the spring, when on a normal farm they’d be planted in the fall, exposing bees to neonics for longer; and the study found no effect on honeybees, Gradish said.
University of Guelph professor emeritus and scientist and chair of toxicology in the school of environmental science, Keith Solomon, said the data he’s seen and the research he’s done has led him to a simple conclusion. “In terms of honeybees, provided people are not being stupid and are using sound agricultural and apicultural practices, it’s a very small risk associated with the use of neonics.”
Solomon reviewed the five studies for Farmers Forum and concluded that their low-level analysis isn’t useful for a risk assessment. “They’re insecticides. Of course they can kill bees,” he said. “An insecticide will kill (honeybees) at a high enough dose. But when you look at the actual studies done on honeybees, the in-the-field exposures are not the same.”
