The underappreciated world of biocontrol

Naomi Cappucino researches biological control at Carleton University.

Wearing grey dress pants and a professional, floral blouse, Naomi Cappuccino tramped through a clearing overwhelmed by dog-strangling vine. The vines, once green and growing a metre high, had yellowed and collapsed in the face of winter. Their seeds, a larger version of dandelion fluff, littered the field like remnants of a pillow fight. 

Cappuccino leaned over and grabbed a fistful of vine. Fluff flew into the air, some sticking to her pants. “Their seeds last for several years,” she explained. “They’re almost impossible to get rid of.”  

Cappuccino, a Carleton University biology professor and a researcher at the Central Experimental Farm, works in the field of biological control. Biocontol aims to combat invasive species by importing their natural enemies. The clearing, just across the canal from Carleton University, has been the site of her research for the past year.

“It’s an environmentally friendly way to control pests,” Cappuccino said of her career, “and we have pests that need controlling.”

Target number one right now is the dog-strangling vine, an Eastern European plant taking over the Ottawa area. In late September, after a ten-year process, Cappuccino and her co-workers finally released 500 of the Ottawa environment’s supposed saviours—the Hypena opulenta caterpillar.

Dog-strangling vine first appeared in the Ottawa area around 100 years ago, when curious botanists brought over samples from Europe. Early botanists often didn’t understand what a non-native plant could do to an ecosystem. It wasn’t until the last 15 years, however, that the vine began to take over. Scientists are not sure why, but so far, the vine has spread throughout Ontario and into New York state.

The vine is resistant to pesticides and extremely difficult to uproot. Volunteers in Ottawa have tried to dig it up with little success.

“It’s everywhere,” Cappuccino lamented. “They’ll try and yank it out, but it’s futile.”

With the introduction of the caterpillars, Cappuccino hopes this will change. The caterpillars are a natural predator of the vine. They originate from the Ukraine, so they are able to survive cold Ottawa winters. They have undergone an extensive testing process to make sure they won’t feed on any plant besides the vine, and so far this has been a success.

When asked about them, her face lit up. She brought out a red-capped Rubbermaid container and tenderly removed the lid. Inside, two small green caterpillars crawled across some leafy twigs and bunched up paper towel.

“I brought these home to show my daughter and kind of raise as pets,” she explained.

She paused.

“I should go grab some more leaves for these guys,” she said as she made her way to a small tree and ripped off a couple twigs. When she returned, there was a leaf in her well-coifed grey hair.

Love of bugs is what first got Cappuccino into biology. As a child, she used to raise caterpillars in a cage on her family’s cherry tree. Now she raises them at a national laboratory.

Cappuccino, who originally studied population ecology, moved into biocontrol around ten years ago because she wanted to do something with practical application. “I decided I wanted to do some good in the world,” she explained. “It was a bit of a mid-life crisis.”

With a new field came a new challenges. In the past, there have been well-publicized biocontrol failures. The cane toad was brought from Hawaii to Australia in 1935 to fight against the native grey-backed beetle, a pest that feeds on sugar cane. The toad now runs rampant, but never made any impact on the beetles they were supposed to eat. Instead, it spreads diseases and affects local biodiversity. Because of early mistakes, biocontrol is now a closely regulated field.

“If anything, we’ve gotten so strict that it becomes difficult to get permission to do anything,” said Cappuccino. “We should have gotten permission to release those caterpillars three years ago.” Cappacino, who has been a researcher on the caterpillar project since its beginning, admits the back and forth process that research involves is sometimes frustrating.

Researchers must make sure that a potential biocontrol agent will only eat the invasive species. Tests must first be done in Europe. Once the agent is brought to Canada, it is tested all over again. Then, before release, a panel of scientists from across North America must examine it.

This back and forth leads to one of the big challenges of biocontrol – funding. Scientists who go over to Europe may not find a biocontrol agent, or only find ones that are unsafe to release because they will eat other things.

“Nobody wants to spend money on something that risky, so getting money is nearly impossible,” said Cappuccino.

This lack of funding also makes it hard to measure the long-term success of experiments. “When you’re planning a study, you’re thinking three years,” Cappuccino explained. “If you don’t publish in three years, you lose your funding.”

Cappuccino calls this a hit-and-miss approach. If an invasive species declines, researchers don’t know by how much, or if their agent was the cause. But these kinds of studies would require more funding, which the field doesn’t have.

Sometimes biocontrol is a straight-forward success. After a team Cappuccino was a part of released a biocontrol beetle in the early 1990s, the invasive purple loosestrife plant that the beetle was ment to target almost disappeared from the Ottawa area.But even in this case, researchers don’t know why an agent succeeded. And because there is no concrete evidence of achievements, biocontrol success stories are ignored in the media.

Next year, Cappuccino and co-researchers will see if the caterpillars have survived the winter. Then, if all goes well, they will release more onto the Experimental Farm plot and perhaps in other areas across Canada. They will also examine how well the bugs spread on their own.

But will Cappuccino’s caterpillars be able to eradicate dog-strangling vine? Only time—and most likely not scientific study—will tell.