Scarcity of slugs has U of A biologist urging gardeners to dig some up for her research

The University of Alberta’s slug lab needs help from home gardeners. They are looking for your slugs, to further their research into naturally controlling the slug population.

Supply is drying up for biologist searching for natural enemy

University of Alberta researcher Lien Luong hopes to find a natural enemy for the slimy, destructive critters.

While many home gardeners are celebrating a slug-free summer, a University of Alberta biologist has issued an all-points bulletin for the slimy critters to ensure her research doesn't dry up. 

"It's definitely been an issue because [it's been] unusually dry this summer," said Lien Luong, an assistant professor in biological sciences department who is several years into research on how to control slug populations without the use of chemicals.

Other years, Edmontonians have brought in their slugs by the thousands, she said. But even with recent rain, Luong is seeing only a fraction of that number.

"We're getting some slugs coming in from homeowners who donated slugs in the past," she said. "We're getting a few hundred here and there."

Nematodes as the nemesis

Luong's research is focused on whether nematodes, a parasite also known as a roundworm, could become a natural enemy of the lowly slug.

It's already being used to control slugs in the United Kingdom and elsewhere in Europe but a similar species of nematode was only discovered in Canada in 2019.

"We want to know how effective it is at killing the slugs in Canada. So there are a few things that we have yet to understand about this specific strain that we found in Canada," she said.

Send your slugs

That's where gardeners come in.

Luong says there is an art to catching slugs

"Go out into the garden in the early mornings or around dusk when it's cool and humid. And then you can handpick or use like a spoon or something," she said.

"You can put them into like a yogurt cup or margarine container with a little bit of like damp paper towel or some leafy material."

The lab can be contacted by email slugs@ualberta.ca

And unlike most of us, Luong says the lab can never have too many.

"We actually freeze the ones that we don't need immediately and then over the course of the year, because we don't get slugs after October, we defrost them as needed." 

Double duty

The slugs will be used in two ways by Luong and her team: to research what type of parasites naturally kill slugs out in the field, and being fed to the nematode to see if the parasite successfully kills the slugs.

"It turns out that the grey garden slug species, which is most commonly found in home gardens, didn't have any parasites," Luong said.

"That may explain why they're so prolific. But the nematodes in the lab can grow on them. So we're asking people to donate their garden slugs to help us propagate the nematode."


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