Volunteers scramble to save trees from gypsy moth caterpillars | CBC News

A group of volunteers will spend the next several months pulling invasive gypsy moth caterpillars from trees, and destroying them, before the insects defoliate an urban park in Ottawa.

The gypsy moth caterpillar runs only four to six centimetres long, but that minor insect poses a massive threat to Ontario’s forest cover.

Scientists warn that 2021 shapes up to be a bumper year for the invasive species, brought to North America around 1860 by a French entomologist who hoped to cross-breed them with silkworms.

With the help of fellow tree protectors, Sharon Boddy visits the 11-hectare Hampton Park nearly every afternoon wrapping trees in burlap and hand-picking the caterpillars off tree trunks and branches.

She then kills them off with soapy water.

“We’re in year two of an infestation and it’s hitting Ontario really, really badly,” Boddy said.

“We need to get a jump on it now because this isn’t the last year.”

Gypsy moth caterpillars are distinguishable by their red and blue dots and skin-irritating hairy backs. They can be found in clusters along many of the trees in Hampton Park. (Celeste Decaire/CBC)

Boddy says the work, which can sometimes get a little messy, will continue into the fall and she hopes to recruit more volunteers along the way.

“The worst part is getting rid of them after they’re dead,” Boddy said. “Sometimes we’ll come across the pupae and they kind of squirt at you.”

Sharon Boddy talks about protecting trees from gypsy moth caterpillars:

Resident Sharon Boddy says many of the trees in Hampton Park are threatened by gypsy moth caterpillars, driving volunteers to trap and remove as many of them as possible. 1:45

‘It’s pretty hard to control this’

Research scientist Christian Schmidt said these insects don’t have any natural predators because they are not native to Canada. They are not part of the natural food web.

“People have spent millions of dollars trying to control this thing over the decades,” Schmidt said.

“It’s unfortunately a situation of, once the cat is out of the bag, it’s pretty hard to control this.”

While alarming to see some trees completely defoliated by these bugs, Schmidt says he’s not concerned about long-term damage as the population is cyclical and will eventually decrease.

Sharon Boddy uses soapy water to drown and kill the gypsy moth caterpillars after volunteers pluck them from the trees. (Celeste Decaire/CBC)

He does commend the work of Boddy and other volunteers in Hampton Park.

“It’s certainly beneficial to trees that are being severely defoliated because you’re reducing the stress on that tree,” Schmidt said.

“And in a year like this, when there’s already drought conditions in the spring, trees are experiencing other stressors.”

The City of Ottawa’s forestry department said staff has monitored the situation closely and encourages residents to continue to physically remove caterpillars and wrap the trees with burlap.

The city has said they might begin intensive surveys to determine areas of concern, as well as communicate to residents and community groups about how to protect trees for next year’s invasion.