Pesticide Free Education Program Failure | Port Moody Can’t Walk the Talk On Organic Pesticides |City of Port Moody : The European Chafer

The European chafer (Rhizotrogus majalis) is an introduced insect to British Columbia that has become a serious lawn pest in the Lower Mainland. Since it was first discovered in New Westminster in late 2001, its geographic range has spread considerably throughout several Lower Mainland communities, including within the borders of Port Moody. 

The European chafer beetle is most damaging during its grub or larval stage. Grubs feed on roots of many different plants, but prefer the fibrous roots of turf grasses. Damage can be masked by abundant moisture in spring and fall, but drier weather reveals an emergence of brown patches. Major damage to lawns occurs when, birds, skunks and other predators turn over the lawn in search of these large white grubs in early fall and spring. The adult beetles seldom cause any significant damage. They are short-lived and do not bite or sting.

Learn more about prevention and control measures:

• Description and Identification
• European Chafer Biology
• Prevention
• Identification and Response 

Description and Identification 

The adult beetle is tan coloured, measures approximately 1.5 cm in length, and resembles small June beetle. The grubs, measuring 2 to 2.5 cm, are soft, white, and C-shaped, with tan-coloured heads and six prominent legs. A microscope is required to confidently identify the grubs.

Appearance of European Chafer
Grubs in Dirt  

Scale of European Chafer Grubs

Adult European Chafer

Images retrieved from Ministry of Agricultural Lands Website at:http://www.agf.gov.bc.ca/cropprot/chafer.htm

European Chafer Biology

Image Adapted from the Landscape Ontario Horticultural Trades Association

April-Late June:

• Adult beetles emerge from the soil on warm evenings and fly to broad-leaved trees to fed and mate in swarms. The adult beetles do not cause damage to lawns at this time.

July-September:

• In June and July, mated females return to grassy areas where they can lay up to 50 eggs in the soil. The eggs hatch in about 2 weeks and the small grubs begin to feed on the roots of grass. During this time, damage to lawns results in dying patches of grass.

October-March:

• The grubs grown and continue to feed in the fall and winter, where they remain within 5cm of the ground. The grubs continue to feed until they grow into adult beetles in May. Most of the damage to lawns occurs at this time, as birds, skunks and other predators turn over the lawn in search of the growing grubs.

Chafers complete their life cycle in one year, which can lead to rapid population increases. Additionally, as they are an introduced species, they have few natural predators to control their population and are difficult to eradicate. There are several ways to control and manage the European chafer and its impacts. 

Prevention – A healthy lush lawn is your first line of defense!

• Healthy Lawn Maintenance- Increase mowing height (to 8-10 cm) and water your lawn deeply (to 2-3 cm). Tall and lush lawns are less prefer by egg-lying female beetles. Longer grass also means longer root systems that are more resilient to larval feeding. Additionally, naturally fertilize your lawn with organic fertilizer to maintain a healthy lawn.
• Alternative Landscapes – Alternative low-maintenance ground covers plants can also be considered. There are several aesthetically pleasing options, which include Dutch white clover, creeping thyme, kinnikinnick, salal. Some residents have even considered the option of ornamental grass.
• Exterior Lighting Reduction – As mating chafer beetles are attracted to light, reducing exterior lighting on your property during the mating and egg laying season in June and July, can ultimately reduce the number of grubs in your lawn.

Identification and Response: 

Infestation Identification:

• Foraging birds, skunks and other predators are also a sign of a possible grub infestation.
• Additionally, an infestation may lead to your grass feeling spongy (due to tunneling of grubs), and appearing wilted or dead.
• Take the infestation monitoring test:
  • Cut 3 sides of a 30 by 30cm square of sod to a depth of 5cm;
  • Fold each square back and count the grubs;
  • If more than 5-10 grubs are found per section, chafer control may be necessary.

Lawn Damage Cause by Animals Foraging for Chafer Grubs

Source: Adapted from the Landscape Ontario Horticultural Trades Association

Response Options:

• Biological Control -In combination with healthy lawn care practices, the application of nematodes, naturally-occurring microscopic worms, has been effective.
  • Nematodes seek-out, infect, and kill grubs, and are not hazardous to humans, animals or the environment;
  • Local garden supply stores carry products that contain the Heterorhabditis bacteriophora nematode, which is the specific species of nematode that used for chafer control;
  • Nematode treatment is most effective in late July after the hatching of chafer eggs.
• Consider Lawn Conversion – Converting to alternative low-maintenance ground cover should be considered. Effective options include, Dutch white clover, creeping thyme, kinnikinnick, salal, ornamental grasses, or rocks.
• Barriers – Set up barriers around infected areas to prevent foraging predators from turning the lawn. Fences, netting, or chicken wire are all effective options.

If you have an ongoing problem with European chafer, consider employing a professional company to help address the issue in a comprehensive manner.

Additional Information: 

European Chafer: A Management Strategy for the Lower Mainland- A Fact Sheet and Management Calendar 

The City of Port Moody does not allow pesticides or chemicals to treat chafer beetles, as per Bylaw No. 2575: 
Pesticide Use Control Bylaw No. 2575