Use caution banning pesticide: researcher: honeybee killer can have practical applications.

• Author: Kelly, Lindsay
• Position: FORESTRY

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Neonicotinoids--a type of pesticide used in agriculture and horticulture --have been implicated in honeybee colony collapse, but one scientist doesn't believe a full ban on the pesticide is necessary, especially as it applies to forestry.

David Kreutzweiser, a research scientist in the Forest Ecosystems Research and Assessment Team at the Canadian Forest Service in Sault Ste. Marie, was one of three Canadian research scientists appointed to the Task Force on Systemic Pesticides initiated by the International Union for Conservation of Nature's Commission on Ecosystem Management.

Charged with reviewing 1,100 studies and reports on the topic, the task force released its findings in 2015, determining that neonicotinoids do adversely affect honeybees and, as a result, the surrounding ecosystem.

"Studies demonstrated that honeybees can receive an acute, lethal, toxic dose from a single flight through a dust cloud during seed planting, for example," Kreutzweiser said during an April webinar.

"But perhaps more insidious was that increasing evidence shows that honeybees were also experiencing sub-lethal, harmful effects from prolonged exposure to low concentrations."

Long-term exposure of low doses made the bees disoriented so that they didn't return to the colony, and they had lower resistance to disease and other stressors, which led to an overall decrease in colony efficiency, he said.

An unfortunate result, Kreutzweiser said, could be lower pollination levels in areas where neonicotinoids are being used extensively.

Similar impacts were found on other species as well, such as aquatic invertebrates.

In PEI, for example, small amounts of the pesticides, used in potato production, have led aquatic invertebrates to stop feeding and reproducing.

In the Prairies, where neonicotinoids are used extensively in canola production, the pesticide has been found year-round in shallow bodies of water called "potholes." The permanent presence of the pesticide reduces the amount of aquatic invertebrates, which reduces the emergence of insects, which results in less food for bird species, reducing bird reproduction, Kreutzweiser said.

In Ontario, with the onset of the emerald ash borer, researchers examined the impact of neonicotinoids on leaf matter, which is consumed by earthworms and aquatic insects.

The pesticide's presence caused the...