British Columbia

Vancouver deploys microscopic nematodes in chafer beetle battle

The Vancouver Park Board is 'partnering' with a group of fighting nematodes — microscopic roundworms — to destory the chafer beetle.

Nematodes are microscopic roundworms that attack chafer beetle larvae

Now is the time to release the nematodes. (Oregon State University)

The Vancouver Park Board is deploying a tiny defender in its battle against the invasive European chafer beetle.

It's treating 31 sports fields with nematodes — a microscopic roundworm that feeds on chafer beetle larvae.

Brian Quinn, Manager of the Parks Operations for the Vancouver Park Board, said that nematodes are the most environmentally friendly application to help control chafer beetle populations.

The Vancouver Park Board is taking on the invasive European chafer beetle — pictured here — with a little helper. (Rafferty Baker/CBC)

"The nematodes are non-toxic. They're a biological control so they don't pose any hazard to human or animal life."

Attacks the beetle when it's vulnerable

Quinn said it's key to apply the nematodes now because this is when the chafer beetle is in its larvae stage and most vulnerable to the nematodes.

Without treatment, the chafer beetle continues to feed throughout the fall and winter.

In spring, birds, skunks and other animals turn over infested turf searching for the grubs, destroying lawns and fields.

"We certainly don't want to experience what we experienced this spring next year," he said. 

"So we've got our forces out there putting up some defences now to help control the populations for next spring."

Vancouver Park Board manager Brian Quinn hopes the nematodes can combat the chafer beetle infestation that damaged 31 city playing fields last summer. (Maragaret Gallagher/CBC)

Homeowners can also use nematodes (available in most garden centres) in their fight against the chafer beetle, but but they need to be wary of water restrictions.

Water, water, and repeat

Quinn said watering is essential to applying the nemotodes because the organisms "use water as a way of navigating through the soil to get to the larvae of the chafer beetles".

Lawns must be moist before applying nematodes, and watered afterwards to push the nematodes into the root zones.

"You want to water them in to get them down to the root zones. Not just once, but over a period of 10 days to 2 weeks just to make sure down there," he recommended.

In fact, it was precisely because of strict water restrictions last summer that the city wasn't able to apply the nematodes last year.

Nematodes — sold as a floury substance, far left — are added to the the water tank and the solution is then sprayed onto the field. (Margaret Gallagher/CBC)

The hot and dry summer of 2015 led to substantial chafer beetle damage to many city fields.

And a word of caution — homeowners should apply for a watering exemption permit from the city if they want to properly apply nematodes.

But Quinn said "even with the current water restrictions, a homeowner without a permit should be able to apply nematodes by watering on their permitted days."

The city also says homeowners can avoid chafer beetle infestations by keeping their lawns healthy and maintained, and considering grass replacements such as mulch or paving stones.

With files from Margaret Gallagher.

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A lawn near Kits Point destroyed by chafer beetles. (Margaret Gallagher/CBC)