If your lawn is looking patchy, brown, or unexpectedly spongy underfoot, lawn grubs might be the culprit. These underground pests are a dreaded nuisance since they devastate healthy turf by feeding on grass roots, leading to widespread lawn damage if left untreated. In Ontario, grub infestations typically strike during late summer and early fall, making early detection and proper treatment important.
Here’s what you need to know about identifying, controlling, and preventing lawn grubs.
What Are Lawn Grubs and Why Are They a Problem?
Lawn grubs are the larval stage of beetles, most commonly the European Chafer, Japanese Beetle, and June Beetle. They live just beneath the soil surface and feed on grass roots, cutting off the plant’s ability to absorb water and nutrients. Over time, this leads to brown patches, turf that lifts easily, and weakened grass that’s more vulnerable to drought and disease.
Grub infestations are particularly damaging in late summer and early fall, when larvae are at their hungriest. Without intervention, this damage can persist into the next growing season.
Signs You May Have Grubs in Your Lawn
Grub damage can sometimes be mistaken for drought stress or fungal issues. Here are key signs to watch for:
- Brown or dead patches of lawn that expand over time
- Turf that lifts easily, like a loose carpet, due to root damage
- Increased bird or raccoon activity, as animals dig up your lawn to eat the grubs
- Spongy texture that’s noticeable when walking across affected areas
- Visible white C-shaped larvae when you peel back the sod
If you spot more than 5–10 grubs per square foot during inspection, it’s time to act.
Grub Control Solutions That Work
Timing is crucial: treatments are most effective when grubs are small and actively feeding.
- Nematodes: Beneficial nematodes (microscopic roundworms) are a natural predator of lawn grubs. Apply in summer when grubs are young and near the surface.
- Proper lawn care: Healthy, well-maintained turf can outcompete mild grub activity. Aerate compacted soil, overseed thin areas, and water deeply but infrequently.
- GrubBGon® or similar bio-insecticides: Safe for pets and pollinators, these biological solutions use bacteria that specifically target grub larvae without harming your lawn.
- Traditional insecticides: In severe infestations, products with active ingredients like imidacloprid can be applied in late spring or early summer, but always use with caution and consult a licensed professional.
How to Prevent Grub Infestations Long-Term
Grub prevention starts with proactive lawn care:
- Keep your lawn thick and well-fed. A dense turf canopy makes it harder for beetles to lay eggs.
- Monitor early in the season. A quick inspection in late spring can catch grubs before they cause major damage.
- Mow high (7–8 cm) and leave clippings to nourish the soil.
- Water regularly in early summer/late spring. Moisture is needed when grubs/adults are flying in June – water reduces egg laying.
- Avoid overwatering after June. Too much moisture creates ideal conditions for grubs once eggs are laid.
Trust Wright Landscape Services for Lawn Grub Control
At Wright Landscape Services, we offer integrated lawn care programs that address grub infestations with environmentally responsible techniques and expert oversight. Whether you’re dealing with an active problem or want to prevent one, we’ll tailor a solution that suits your property’s needs.
Contact us today to schedule a grub inspection or learn more about our year-round turf health programs.
