Winnipeg's hole-burrowing Richardson's ground squirrels are up against a new enemy this summer - 'The Giant Destroyer.'

The City of Winnipeg has been forced to change tactics in its ground war against Richardson's ground squirrels. Last spring, a pet dog ingested some poison used to combat the gophers, prompting the city to rethink how to control the population.

The Saskatchewan Roughriders Football Club saw fit to make a gopher their official mascot, but in some Winnipeg parks the furry rodents are on a hit list for making holes and injuring walkers and sports team players.

This spring, the city will use a fire-cracker-like incendiary device called The Giant Destroyer.

Crews will light a fuse and stuff the cartridges containing sulphur and sodium nitrate into gopher burrows. The resulting smoke will gas the gophers.

Pet owner questions use of chemicals

Heather Wieler takes her dog Mister on frequent visits to Little Mountain Park. She acknowledges the gopher holes are a danger to walkers, both of the human and canine variety, and to sports enthusiasts and joggers.

But Wieler worries about what the smoke from The Giant Destroyer will leave behind.

"I'm not a huge chemical person. I always think there is a natural...nature's way of doing things," she said.

Wieler remembers they used to pump water into the burrows on her family's rural Manitoba property to drown out or relocate gophers and other critters. She says gopher patrols used to be a way to pick up pocket money for kids.

"The municipality used to pay farmers for however many gopher tails they got and that encouraged teenagers with pellet guns to go have a fun afternoon. But I guess in a public park that's not a feasible thing," she said.

Chemical cartridges to be used in a dozen city parks

Dave Domke is the manager of parks and open spaces for the City of Winnipeg.

He says there are about a dozen parks in Winnipeg where The Giant Destroyers will be deployed.

He says the cartridges have been approved for use by Health Canada's Pest Management Regulatory Agency and the residue from the sulphur smoke is not a hazard.

"They are really a lot safer than the product we used last year," he said. "They are a gas, so the gas will just dissipate up into the air."

There is an almost bewildering array of choices to control ground squirrels.

Taz Stuart, the director of technical operations for exterminator company Poulin's Services and a former city entomologist, says the company does plenty of gopher control for both residential and government clients.

"It's a three day job. It's not just going in, doing the treatment and saying - see you later," he said.

Stuart says Poulin's can set traps for the ground squirrels or will deploy pellets the company developed in-house, called Gopher Doom.

He says Poulin's also sells The Giant Destroyers cartridges, but warns they must be deployed a minimum of five metres from buildings to prevent the sulphur gas from seeping indoors.

University of Manitoba researcher James Hare doesn't like the use of poisons.

"It's just a miserable way to go," Hare told CBC News when the city announced it wouldn't be using poison.

Hare says trapping and euthanizing the gophers was much more humane.

The City of Winnipeg is also looking at a pilot program using carbon monoxide gas to exterminate the gophers.

Those tests won't begin until the ground has thawed and the gophers are active.