Researchers hoping hungry caterpillars can thwart invasive species

A group of researchers at Ottawa’s experimental farm is hoping to use some hungry, hungry caterpillars to help control a vine that is pushing its way across farmers' fields.

Dog-strangling vine has spread across Canada, but researchers may have found a weapon to stop it

Tyler Smith, a researcher with Agriculture and Agri-Food Canada, is working on the project. (Stu Mills/CBC)

Researchers at Ottawa's experimental farm are hoping to use some hungry, hungry caterpillars to help control a vine that is pushing its way across farmers' fields.

Dog-strangling vine is an invasive species that is gaining root across farmer's fields and backyard gardens in Canada. It's surviving Canadian winters easily and can really only be removed with backbreaking efforts.

"In Ottawa, we see it all over the place, getting into old fields and hedgerows," said Dr. Tyler Smith a researcher with Agriculture and Agri-food Canada. "There is no effective way to control it."

Ottawa researchers hope hungry caterpillars will help bite off invasive plant 0:55

Smith is working with a team that is researching  a caterpillar called hypena opulenta that eats the plant and can help control it.

"It is not ever likely to get rid of it entirely, but if it can control it so that the native plants have a chance to compete again, then it can protect a lot of the bio-diversity in our landscape."

Exhaustive testing 

Smith said there are actually a lot of details to control for in a case like this, including confirming that the caterpillars can  survive here in Canada and that they aren't going to become a whole new invasive species.   

"We're making sure that we have all our bases covered and we are not going to make anything worse," he said.

The team is testing the caterpillars on plants grown in both shade and sun, and is testing other variables to see what leads to the most success.

Alicia Rochette, a master’s student at Carleton University working on the project, has helped on the experiments testing how the caterpillars do in a wide range of conditions. (Stu Mills/CBC)

Alicia Rochette, a master's student at Carleton University working on the project, said the research team wants to give the caterpillars all the help possible to damage the plant.

"We want to release the larvae where they are going to be successful," she said.

She said the caterpillars don't kill the plant, but they can significantly weaken it.  

"Our hope is that we will get large enough numbers that you will get a lot of damage around the plant and slow them down."

The caterpillars eventually become moths that can lay eggs and spawn new caterpillars. (Stu Mills/CBC)

Still more work ahead

Smith said the team still has a lot of work to do, but has cleared some of the major hurdles by getting the caterpillars to the moth stage and having them survive winter.  

He hopes eventually they will be sent to farmers to help control the vine.

"We will eventually get to the point where we are distributing the moths, but we are years away from that."

How did "dog-strangling vine" get its name? 0:28

With files from Stu Mills