How to stop the European chafer beetle from destroying your lawn
Is this “monster” living in your backyard? The odds are high if you notice crows or skunks digging up the grass. The European chafer beetle is a new pest in B.C. and is spreading fast in Vancouver, Burnaby, New Westminster, Coquitlam, North Delta, and Richmond.
European chafer completes its life cycle in one year. Adults emerge in late May to early July, fly to nearby trees to mate, and each female deposits about 50 eggs below the soil, which hatch in mid July. The larvae (grubs) have C-shaped bodies and feed on turf roots all fall. During winter they dig down for periods of freezing conditions, and resume feeding in spring until April when they become pupae. Adults are tan colored and do not cause any damage.
Homeowners should mow at five to eight centimetres high during adult activity period, as egg-laying female beetles do not prefer taller turf. To inspect your lawn, cut several test sections 12 inches square and look for white grubs. If you count five or more grubs, control is warranted. Healthy, well-maintained turf can withstand low levels of grub feeding. Although digging by birds, skunks, and raccoons damages turf, it also helps decrease the pest populations.
Bio-pesticides containing “cruiser” nematodes are available for grub control, which work best if applied from late July until September when grubs are relatively small. Research shows that some naturally occurring soil organisms also infect grubs and make them sick, reducing their impact.
Rana Sarfraz is a researcher at UBC who is studying the disease susceptibility of European chafers and is hoping to identify a more effective microbial product for their control.