Ottawa scientists seek insect ally against ‘dog-strangling vine’

A researcher at Carleton University in Ottawa is looking hard for an insect that could potentially control a destructive European weed invading the Ottawa area.

Dog-strangling vine or pale swallowwort is native to Russia. It is harmless to dogs but does kill the plants around it by changing the acidity of the soil.

Carleton University biologist Naomi Cappuccino suspects the vine was introduced to the Ottawa area by botanists who found the plant interesting. Unfortunately, there are no organisms native to the region that eat the plant, so its spread has been hard to control.

It is now pushing into Gatineau Park, across the Ottawa River, and has been spotted as far away as Kingston.

Cappucino and her students have been searching for the past five years for a European insect that could do the job.

She said a root-feeding beetle from Russia and two leaf-chewing caterpillars look promising, but scientists must do about five more years of research to ensure the insects won’t also harm North American plants.

Cappucino said a similar approach was successful at controlling purple loosestrife, another invasive plant that was a big problem 15 years ago, before two beetles that feed on loosestrife were introduced.

“If you go walking through the greenbelt areas west of town you’ll notice places where there used to be huge purple strands of purple loosestrife,” she said. “And now you’ve just got these little ratty, bitten plants that are all just eaten down to the ground.”

In the meantime, local gardeners are dealing with dog-strangling vine by pulling it out of the ground by its roots.