As the City of Regina struggles with an invasive weed called leafy spurge, it has called in 40,000 reinforcements to help with the fight.

That's how many leafy spurge beetles were released in recent days.

"It's really an invasive plant. It can destroy eco-systems," said Russel Eirich, the city entomologist who is in charge of releasing the bugs.

Each female leafy spurge beetle will lay 300 eggs. When they hatch, the larvae will feast on the roots of leafy spurge plants. (USDA)

In Regina, leafy spurge is choking out the natural grasses that grow along storm channels. Farmers hate it too, because livestock don't like to graze on the spiky plant.

Fortunately, leafy spurge larvae love munching on the roots. Each adult female beetle will lay 300 eggs. It's considered an effective alternative to pesticides.

The city has been collecting the insects at a "beetle development site" west of Moose Jaw, putting them in paper bags and then releasing them on the Regina's east side. On Friday, the bugs were being deployed on Quance Street.

There's little concern that the beetles will themselves become an invasive species, explains Eirich. That's because they have a limited food range — the bugs like leafy spurge and that's about it.

Because leafy spurge already has a strong foothold in Saskatchewan, it's expected it will be years before the bug invasion pays off.

Eirich said he hopes to see results in about three years. Eradicating leafy spurge may not be in the cards, but keeping it under control is the goal.

"It's a fairly big problem," he said.