European Chafer Beetle
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.
Because this invasive species reproduces rapidly and feeds on the roots of all kinds of plants, including grass and turf used for lawns, it has become a serious pest in Vancouver and area.
Why European chafer beetles are a nuisance
They are a nuisance because the grubs feed on the roots of all kinds of different plants, including turf and grass, destroying the plants. Their life cycle is only one year long, which means that their population rapidly increases.
How to know if you have an infestation
- Heavy infestations may lead to your grass 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. Grubs will feed all throughout the winter until they pupate in May.
- The damage these beetles cause can be masked by abundant moisture in spring and fall, but drier weather quickly results in the appearance of brown patches on your grass.
- You may also see birds, skunks and other predators digging up your lawn in search of grubs.
Monitor your lawn for European chafer beetle infestations
The following steps can be taken to monitor your lawn for infestations:
- Monitor the infestation by cutting 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.
How to prevent a European chafer beetle infestation
Prevent a large infestation by keeping your turf healthy. Also, adopt a vigorous maintenance routine involving aerating, dethatching, fertilizing, deep watering and mowing.
In high traffic areas consider grass replacements such as mulch or paving stones, or use alternative ground covers.
What to do if you have an infestation
- Apply nematodes, Heterorhabditis bacteriophora, during the 3rd week of July. Nematodes should be applied in the evening or on a cloudy day.
- 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. You may need to get a water exception permit to allow you to do this.
There is no chemical control option allowable under Vancouver’s pesticide bylaw (health bylaw no. 9535).