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Tiny Asian wasps brought in to fight Calgary’s invasive lily beetle

Click to play video: 'Invasive lily beetle to face menace from abroad' Invasive lily beetle to face menace from abroad
WATCH ABOVE: Lily Beetles are rearing their heads around Calgary gardens, munching through some people’s favourite flower. As Sarah Offin reports, the city may soon have a solution – Aug 9, 2016

If your garden hasn’t been wiped out by constant storms and hail, there could be another menace lurking in the leaves.

“At first I thought they were lady bugs and I thought, ‘oh nice little lady bugs!’ and then soon I realized – they were not,” Banff Trail resident and gardener Rita Gore said.

There’s nothing ladylike about what the hungry little lily beetles have done to Gore’s lilies. The flowers are gone and the leaves are spotted with holes.

The City of Calgary is investigating new ways of combating the invasive lily beetle, which started showing up around Calgary in 2004. Sarah Offin, Global News

“It was my stargazer lilies that were the most devastating because they got right on the buds and they just chew through. So the buds still open up and then they’ve just got holes.”

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With each lily beetle cycle, combatants like rose dust fly off the shelves at garden centres.

“Pretty much two or three times a week… everybody comes on about these red beetles in their garden,” Scott Stoner at Blue Grass Nursery said.

Experts say it’s best to spot them when they’re young. They hide, camouflaged on the underside of leaves.

“They can pretty much strip a lily in three or four days if they’re not kept in check,” Stoner added. “Until we can find a natural predator for them it is something we will have to deal with.”

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Together with the City of Calgary, researchers at Carleton University in Ottawa and Olds College in central Alberta think they may have found a solution: a tiny wasp from Asia that reproduces in (and kills) the lily beetles’ larvae.

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“They’re specialists – they focus specifically and exclusively on that one species,” researcher and horticulture instructor Dr. Ken Fry from Olds College said. “They’re not distracted by other species and so all of their efforts are on hunting down and reproducing in that one host species.”

The first batch of the wasp, called Tetrastichus Setifer, was released on a batch of beetles at Olds College a few years ago. Two additional lily plots in the city are now also being tested. Researchers expect to know whether the wasps are effective beetle combatants by spring of 2017.

“In its home range in Asia, and now in Europe, it’s been very successful in suppressing the beetle’s population to the point that it’s really a non-issue in its home range in Asia,” Fry said. “So we’re hoping that similar results will occur in the west, provided that it can survive our winter.”

Until the pilot project is complete, gardeners are left to find their own solutions in combating the garden pests.

“I just handpick them,” Gore said. “I tried drowning, but now I just… use the stomp method, I guess.”

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