White grubs are insect larvae that live in the soil and can cause significant damage to lawns by feeding on grass roots.
Among the most common species found in Quebec are the European chafer and the Japanese beetle. These insects are considered major lawn pests because they attack the root system of turfgrass.
Depending on the species and temperature conditions, egg laying typically occurs from late May through July.
Once the eggs hatch, the larvae - commonly called white grubs - remain in the soil and feed on grass roots. This feeding weakens the turf, causing it to become yellow, thin, and easy to pull up from the soil.
As winter approaches, the larvae move deeper into the soil to overwinter. The following spring, they transform into pupae, then into adult beetles that emerge, mate, and lay a new generation of eggs.
The life cycle of white grubs varies depending on the species:
- Some species have one generation per year
- Others may have multiple generations per year
- Some species have a life cycle that lasts more than one year
For this reason, it is important to identify the type of white grub present in the lawn in order to determine the most effective treatment.
Signs of a White Grub Infestation
- Yellowing or thinning areas in the lawn
- Turf that lifts easily from the soil
- Increased activity from birds, skunks, or raccoons digging in the lawn
- Presence of C-shaped white larvae in the soil
Inspecting the soil is usually the best way to confirm the presence of white grubs.
What is a white grub?
A white grub is the larval stage of certain beetles, such as the European chafer or Japanese beetle, that live in the soil and feed on grass roots.
When do white grubs appear in lawns?
Eggs are usually laid between late May and July, and the larvae feed on lawn roots throughout the summer and early fall.
How can I tell if my lawn has grubs?
Infested lawns may show yellow or thinning patches, and the turf may lift easily like a carpet. You may also notice animals digging in the lawn to feed on the larvae.
Are white grubs found in the Montreal area?
Yes. White grubs are found in many regions of Quebec, including Greater Montreal, Laval, Longueuil, Brossard, the South Shore, and the North Shore, where they can damage lawns.
Do all white grubs have the same life cycle?
No. Some species have one generation per year, while others may have multiple cycles or a life cycle that lasts more than one year.
Why is species identification important?
Identifying the species helps determine the most effective treatment and the best timing for intervention.
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