Got Grubs?
- Jun 14
- 3 min read
Updated: 2 days ago
What to Watch For and How to Control Them Naturally
If you've noticed brown patches in your lawn that don't seem to improve with watering, grubs may be the culprit. Grubs are the larval stage of several beetle species, including Japanese beetles and European chafer beetles. These pests feed on grass roots beneath the soil surface, causing significant damage to lawns throughout Ontario.
Fortunately, there is an effective, environmentally friendly solution: beneficial nematodes.
What Are the Signs of Grub Damage?
Grubs feed on the roots of your grass, preventing it from taking up water and nutrients properly. Common symptoms include:
Brown or dead patches that do not recover with watering
Grass that feels spongy when walked on
Turf that lifts easily like a piece of carpet
Thinning lawn areas during summer and fall
Increased activity from skunks, raccoons, crows, or other animals digging for grubs
If you pull back a section of affected turf and find several white, C-shaped larvae in the soil, grubs are likely the problem.
Why Choose Beneficial Nematodes?
Beneficial nematodes are microscopic, naturally occurring organisms that seek out and kill soil-dwelling pests such as grubs. They are safe for:
Children
Pets
Pollinators
Earthworms
Birds and wildlife
Unlike traditional pesticides, nematodes work with nature to reduce grub populations without harming beneficial insects above ground.
When Should Nematodes Be Applied?
For best results, we recommend using the beneficial nematodes from Natural Insect Control, twice per year.
Spring Application
Late April through early June
The spring application targets grubs that survived the winter and have resumed feeding as soil temperatures warm. The soil temperature should be minimum 10°C to apply.
Fall Application
Mid-August through late September
The fall application is the most important treatment. It targets newly hatched grubs when they are young, small, and most vulnerable to control.
Applying at both times helps break the grub life cycle and provides the best long-term reduction in grub populations.
How to Apply Beneficial Nematodes (see video)
Step 1: Apply During Cool Conditions
Apply:
Early morning
Evening
On a cloudy day
Avoid applying during hot, sunny conditions, as UV light can harm nematodes.
Step 2: Water Before Application
Moisten the lawn thoroughly before applying nematodes. The soil should be damp but not saturated.
Step 3: Mix Nematodes with Water
Follow the package instructions for mixing rates. Keep the mixture agitated while applying to ensure the nematodes remain evenly distributed.
Step 4: Water In Immediately
After application, water the lawn with approximately ¼ inch (6 mm) of water to move the nematodes into the soil where grubs are feeding.
Step 5: Keep Soil Moist
Maintain consistent soil moisture for 10–14 days following application. This helps the nematodes move through the soil and find their target.
What Results Can You Expect?
Beneficial nematodes are not an instant fix. They need time to locate and infect grubs beneath the soil surface. You may notice improved lawn health over several weeks as grub populations decline and grass roots begin to recover.
Lawns with a history of severe grub damage may require multiple seasonal applications to bring populations under control.
Need Help Diagnosing Your Lawn?
If you're unsure whether grubs are causing problems in your lawn, our staff can help identify the issue and recommend the appropriate beneficial nematode treatment schedule for your property.
Healthy lawns start below the surface. Treating grubs naturally with beneficial nematodes is an effective way to protect your lawn while keeping your family, pets, and pollinators safe.
