Invasive Species & Pests

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Invasive Species

Invasive species are those which live, grow and reproduce outside of their natural habitat or range and can have significant ecological and/or economic impacts once they become established.

These introduced species have been brought to BC without their natural predators and pathogens that would normally keep their populations in check in their countries of origin, giving them a competitive advantage over native species.

For more information on invasive plant species please visit the Invasive Plan Species page.

European Chafer Beetle

The European Chafer beetle (Rhizotrogus majalis) is a serious pest in Eastern North America and was first identified in the Lower Mainland region in New Westminster in 2001. It has since spread to many Metro Vancouver municipalities causing severe damage to lawns, boulevards, medians and grass areas in parks.

How can you tell you have an infestation?

If you have crows, skunks or raccoons digging up your lawn, you may have a European Chafer beetle infestation.

Chafer beetles have a one year life cycle and populations build up rapidly. The grubs feed on the roots of many different plants, but prefer the roots of turf grasses. In drier weather, the damage caused results in brown patches appearing in the lawn. Most of the serious turf damage is typically caused by birds and animals digging for Chafer beetle grubs. Damage by animals is most severe in the Spring and Fall when the grubs are increasing in size and feeding near the surface.

What To Do If You Have An Infestation?

The Chafer Beetle is an exotic pest (not native to BC or Canada), as a result, there are few natural predators to control its population growth. They are here to stay, but with healthy lawn care practices, alternative groundcovers and biological treatment, damage from this pest can be controlled on residential properties.

Treatment Options

Lawn Care and Maintenance

Having a healthy lawn is most important in helping to protect against grubs. They have a more extensive root system, and can tolerate more grub feeding. Chafer beetles prefer laying eggs on closely cropped lawns. Don't cut your grass too short. Raise your mowing height to 6 to 9cm (2.5 to 3 inches). Longer grass also helps protect the soil from water loss and encourages deeper root growth.

Pesticide Control

The use of pesticides, such as Merit, for the treatment of Chafer beetle is not permitted in The City of Maple Ridge.
The City’s Pesticide Use Control Bylaw No. 6413 – 2006 restricts the use of pesticides for cosmetic purposes and allows
exemptions only where there is a danger to human or animal health, or damage to buildings and structures.
The use of pesticides are permitted to be used in controlling the invasive species Knotweed and Giant Hogweed.

Biological Control - Nematodes

Studies have shown that the most effective biological control measure is the natively-occurring nematode (or microscopic roundworm) Heterorhabditis bacteriophora. The H. bacteriophora nematode is a “cruiser” species that actively infects and kills white grubs, such as the European chafer grubs. Treatments are most effective if done in late July, after the European chafer eggs have hatched and when the young grubs are most vulnerable to nematode attack. Nematodes are not a preventative measure; they control chafer beetles that have laid eggs in your lawn. Nematodes are safe to use around both people and pets.
Talk to your local garden center experts to find out more about applying your nematodes for Chafer Beetle control, as timing is everything! Late July applications are best, and watering them in is important.

Remember to get your City Lawn Watering Permit which allows you an exemption from watering regulations. The permit is free with proof of your nematode purchase. You will need the permit because the application area must be well irrigated so that there is no dry soil in the root zone. To get more information and to apply for permits, contact the Engineering Department.


Some Lower mainland residents have had some success preventing Chafer beetle infestation with the use of plastic sheeting, or landscape fabric to cover their lawns before dusk (approximately 9 pm) in June and July when the adult beetles area most active. A cover may prevent mated females from laying eggs in your grass and repeating the cycle. (Note that some covers may need removal each morning).

Lawn Renovation & Repair

If your lawn has been severely damaged by animals in search of Chafer beetles, renovating or repairing your lawn is one way of dealing with the lawn damage resulting from this infestation. This solution is labour intensive, and can create a large amount of organic material to compost or dispose of, and will require you to amend your soil.

Take the following steps when renovating turf areas affected by the Chafer beetle:
  1. Gather up the loose turf and a bit of the top layer of soil.
  2. Compost this material or take it to Meadows Landscape Recycling Center for disposal. Alternatively, hire a professional to dispose of the material responsibly.
  3. Add soil (Turf Blend or Boulevard soil mix) and starter fertilizer.
  4. Add seed, rake the seed in and water initially to aid germination.
  5. Water seeded area adequately to maintain moisture.
  6. In a few cases, follow up with nematodes at the appropriate time, likely in July.

Lawn Alternatives: Replacement

Chafer beetle larvae don't attack all plants so you may want to consider an alternate ground cover. Lawn alternatives can be drought and pest resilient and can require less care and maintenance and provide features such as color, flowers and texture. Alternatives include clovers, sedges, Herbs, Ornamental grasses and sedums.
The Chafer beetle will likely remain an ongoing management issue in the region; however, through consistently implementing the recommended best practices, the extent of the impact can be minimized.

Chafer Beetle Treatment Calendar

October - March Greatest bird and animal damage, but there is no effective control at this time of year.
April - June Pre-order nematodes from local garden centre by mid-May for application in late July. Repair damaged areas and maintain established lawns.
July Obtain your free Lawn Watering Permit from the City. Apply nematodes as directed by your local garden centre. Raise mowing height to 6-9cm, and leave clippings if possible. Water 2x/week, following watering restrictions.
August - September Water 2x/week, following watering restrictions. Apply slow release fertilizer.