Turf wars: Fighting the great chafer invasion – In the Garden


By steve Whysall 10 Feb 2011 COMMENTS(3) In the Garden


European chafer beetles have invaded and the lawn has been "devastated" by crows grazing on chafer grubs.

"My grass is certainly not the worst hit. Vancouver is a mess. At least a third of the yards appear to be badly damaged," she says.

"I’m an ordinary gardener and, like most homeowners, I can’t afford a $20,000 landscape makeover."

Kelton says her east-facing lawn looks as if "a rototiller has been at work". She says she is considering ripping out all the grass and installing a lawn-less landscape.

Kelton is certainly not wrong with her impression that chafer beetles are ruining lawns all over Vancouver.

Sophie Dessureault, integrated pest management coordinator with the Vancouver park board, says the chafer beetle is "everywhere in the city" and has infested lawns both north and south of Broadway.

Chafers first arrived in New Westminster in 2001, hidden in nursery stock shipped from Eastern Canada, where they have been a problem since the 1940s.

They are an introduced pest that invades new areas by hitchhiking, often on the back of cars and trucks.

"They are wreaking havoc all across the city," says Dessureault, "and they are definitely challenging the way we think about and manage our lawns. There was a time when all you had to do was mow your grass and water it once a week and you could forget about it.

"That is no longer the case. Today, you have to work very hard to maintain a lawn. It involves dethatching and watering and fertilizing and not cutting the grass too short."

The city is fighting back as best it can. It uses microscopic nematodes to treat "managed turf areas" such as sports fields and golf courses. But homeowners are on their own and have to fork out their own money on nematodes to treat lawns, or take Kelton’s approach and consider completely replacing a grass with a new landscape.

However, there is some light at the end of the tunnel.

Tracy Hueppelsheuser, entomologist with the B.C. Ministry of Agriculture, says there is evidence that in areas where chafer beetles have been established for a time, nature produces a natural fungal entomopathogen — a soil-borne bacteria that attacks and kills the chafer grubs.

"We are cautiously optimistic that things will calm down after a few years and nature will start to restore the balance."

Hueppelsheuser says the ministry has always advocated taking "an aggressive approach" to the problem.

On its website, it says that healthy, vigorous, well-irrigated turf can withstand low-levels of grub feeding.

This is consistent with the received wisdom we have had over the last decade that well-maintained lawns are less vulnerable.

But the ministry also says that one of the tools available for fighting chafer is to use the pesticide, Carbaryl, which is sold under the brand name, Sevin.

However, most municipalities have banned the use of pesticides for cosmetic applications, such as preventing chafer beetles ruining a lawn.

"We don’t make a judgment on the way to eradicate the problem. We just want to make people aware of what tools are available," says Hueppelsheuser. 

Sheila Kelton has decided the time has come to rip out her small front lawn in South Vancouver and plant something else.