The European chafer beetle arrived somewhere around 2001; now the tan-coloured bug may prove unstoppable
Steve Whysall
Sun
Conway Lum displays beetles that are infesting lawns and golf courses across the Lower Mainland. CREDIT: Glenn Baglo, Vancouver Sun
A devastating beetle infestation sweeping the Lower Mainland is expected to destroy thousands of lawns and ruin large grass areas at parks and golf courses unless an environmentally acceptable method is quickly found to stop the invasion.
The European chafer beetle (Rhizotrogus majalis) first surfaced in New Westminster a couple of years ago. Since then, it has spread to Burnaby, where it is currently killing lawns throughout the South Slope area. So far, there are no reported outbreaks in Vancouver.
Experts predict this could spell the end of the perfectly manicured garden lawn in countless neighbourhoods. Homeowners anxious to preserve their pristine lawns are being told the only workable solution at the moment is to be willing to put in much more time de-bugging, watering and fertilizing and repairing damaged grass.
Many homeowners are noticing the problem for the first time this month as they step outside to find large areas of lawn torn up by raccoons, skunks and crows in search of chafer grubs. Lawns are left overturned as if they had been severely power raked.
The tough-shelled beetle is virtually indestructible and especially difficult to eradicate once it gets into an established cycle of reproduction.
Solutions being suggested include the replacement of lawns with hard landscaping such as brick, slate or hardy groundcovers such as kinnikinnick (Arctostaphylos.)
Homeowners desperate to keep their beautiful lawns are being told that if increased maintenance does not work, the only other option is to use pesticides to kill the beetles in their developmental stage.
However, this solution flies in the face of the current trend and popular wisdom to shun the use of pesticides, excessive use of chemical fertilizers, and to save water by allowing lawns to go brown and dormant during the hot summer months.
The chafer beetle has been a problem in eastern North America for many years, but it was first identified as a new insect to B.C. in 2001.
Measuring half an inch long, the adult beetle is tan coloured and resembles a smaller version of the familiar June beetle. The chafer completes its life cycle in one year.
In June and July, it can been seen flying up from the ground into high trees or other vertical objects such as chimneys and telephone poles where it mates before diving back to the ground, preferring lawn areas, to lay its eggs. During the fall and winter, the grubs feed voraciously on the fibrous roots of grass. The problem for homeowners becomes more obvious in spring and early fall, when the grubs come closer to the surface of the ground, making them a tasty morsel for birds, raccoons and skunks.
In spring, the seriousness of the problem is often masked by rain which keeps the grass moist and the damage less noticeable.
When warmer, drier weather arrives in late spring, lawns quickly show the extent of the root damage, with large areas of grass turning into dead, brown patches, especially undesirable in a park or on a golf course.
In July, the adult beetles are frequently mistaken for bees as they fly around in swarms and feed at dusk on the leaves of deciduous trees. Some homeowners have noticed the frenzied beetles crashing against windows. Fortunately, they seldom cause any significant damage.
One way to check if you suspect that your lawn has been infected is to cut a piece of a 12-inch square of turf and fold it back to a depth of two inches. If you find more than 20 grubs, you have a serious infestation.
There are no reliable biological controls. Experiments have been conducted with nematodes — organisms comprising thousands of microscopic worms that infect the beetle like a bacteria — but this method of control has so far proven to be expensive and the results have been unpredictable.
Sophie Dessureault, integrated pest management coordinator with the Vancouver park board, is more optimistic about the effectiveness of nematodes.
“We did some tests last year and the results were very encouraging. We have to do more experiments to see if this is the way to go,” she says.
Insecticides such as diazonon and carbaryl (Sevin) have been found to be effective if applied at precisely the right time in late July or early August after the beetles have laid their eggs to complete their life cycle.
© The Vancouver Sun 2004
