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Pests

European Chafer Beetle
Fact Sheet 

Does your lawn or boulevard look like this?

Have you caught crows, skunks or raccoons digging up your lawn? If so then you may have a European Chafer Beetle infestation.

What is it?
The European chafer, Rhizotrogus majalis, is an introduced insect that has become a serious pest of turf in Eastern North America. It was first discovered in New Westminster in late 2001 and has since spread beyond New Westminster's boundaries.

Description
Adult European Chafers are tan or brown beetles resembling June beetles but measure only about 1.5cm in length. The grubs, measuring 2 to 2.5cm, are soft, white and C-shaped with tan-coloured heads and six prominent legs.

Biology and Damage
Chafers complete their life cycle in one year which can lead to rapid population increases. In British Columbia, the adult beetles emerge from the soil in early to late June and mate in swarms at dusk. In June and July, females lay up to 20 to 30 eggs in the soil. The eggs hatch in about 2 weeks and the small grubs begin to feed on the roots of turf. Heavy infestations may lead to the turf feeling "spongy" due to grub tunneling. Infested turf will commonly be wilted or dead and be easy to pull back, revealing the feeding larvae. Damage is seen in the fall to early spring when the grubs are full-grown. Feeding continues throughout the winter except during prolonged periods of freezing temperatures. The grubs feed until they pupate in May.

The Threat
The grubs feed on roots of many different plants, but prefer the fibrous roots of turfgrasses. Damage can be masked by abundant moisture in spring and fall but drier weather quickly results in the appearance of brown patches. From fall to early spring, birds, skunks and other predators turn over the lawn in search of the large grubs. The adult beetles seldom cause any significant damage. The shortlived beetles do not bite or sting.

Management

Calendar 

Monitoring: To monitor, cut 3 sides of a 30 by 30cm square of sod to a depth of 5cm, and fold it back to count the grubs. Cut 5 sections per lawn. Dig through soil beneath grass and count the number of grubs. If more than 5-10 grubs are found per section, Chafer control may be necessary.

Prevention: Keep your turf healthy and vigorous by routine aerating, dethatching, fertilizing, deep watering and high mowing. This will help it tolerate smaller infestations without showing signs of damage. In high traffic areas consider grass replacements such as mulch or paving stones, or use alternative ground covers.

Biological control: Apply nematodes, Heterorhabditis bacteriophora, during the 3rd week of July. Apply at a rate of 70,000 per square foot, or 750,000 per square metre. Approximately 100 million nematodes should cover a 33×45 ft lawn. Water the lawn for 3 hours prior to nematode application and for 3 hours following nematode application. Nematodes should be applied in the evening or on a cloudy day.

For information related to chafer beetles Nematode watering permits please visit vancouver.ca/engsvcs/watersewers/water/conservation/sprinkling.htm

Chemical control: There is no chemical control option allowable under Vancouver's Pesticide By-law (Health By-Law 9535 )
http://www.agf.gov.bc.ca/cropprot/chafer.htm