The signs
Brown, dead patches that show up in late summer, fall or early spring. Grass that lifts up like a loose carpet because the roots underneath have been eaten. Skunks, raccoons and birds tearing up the lawn, looking for grubs to eat.
Which grubs are in Windsor lawns?
Most lawn grubs in Ontario are the young of European chafers and Japanese beetles. You may have seen the adults: chafers swarming around trees at dusk in early summer, and shiny green Japanese beetles on plants later on.
Check for yourself
At the edge of a brown patch, cut three sides of a square about a foot across and peel the grass back. Grubs are white, C-shaped and about the size of a fingernail. A few are normal in any lawn. More than about 5 to 10 in a square foot is usually enough to do damage.
Why the damage shows up when it does
The beetles lay their eggs in lawns in early summer. The grubs hatch and eat roots from late summer into fall, move deeper into the soil for winter, then come back up and feed again in spring. That's why lawns brown out in those two seasons.
Treatment in Ontario
Ontario restricts most chemical pesticides for cosmetic lawn use, so the usual treatment here is beneficial nematodes: tiny worms, watered into the lawn, that hunt grubs in the soil. They work best in late summer and early fall, while the grubs are young and close to the surface, and the lawn has to be kept damp before and after.
How to apply nematodes
- Water the lawn well the day before.
- Apply them in the evening or on a cloudy day, because sunlight kills them.
- Water them in right away.
- Keep the lawn damp for a couple of weeks after.
What month should you treat for grubs?
Late summer to early fall, while the grubs are young and close to the surface. In Windsor-Essex, that usually means August and September.
Is October too late for grub control?
It can be. Nematodes need warm soil, and grubs move deeper as the ground cools. Early October can still work in a warm fall. After that, it's usually better to plan for spring.
What kills lawn grubs instantly?
Nothing does. Beneficial nematodes take time to work through the soil. If big areas are already dead, new sod is the fast fix.
Fixing the damage
If the grass is only thin, raking out the dead patches and overseeding can bring it back. If big areas are dead, new sod is the faster fix: the old lawn comes out, the ground is levelled and fresh sod goes down.
Can a lawn come back after grubs?
Yes, if the base of the grass is still alive. Thin patches can fill back in with overseeding. If the grass lifts up like carpet and there's nothing green left, it's usually faster to replace that section.
Keeping them away
A thick, healthy lawn is the best defence. Mow high, around 3 inches, and water deeply but less often. Thin, short, dry lawns are where the beetles like to lay their eggs.
What it costs
Getting rid of an active grub problem on a typical Windsor lawn runs about $350–$750, and a prevention treatment about $250–$550, before HST. If big areas are already dead, replacing them with new sod runs about $1.50–$2.00 per sq ft.
Not sure it's grubs?
Brown patches can also come from drought, dog spots or lawn disease. We check at the free estimate and tell you straight what's going on. Call or text 519-567-4724.
Think you've got grubs?
Free on-site estimate anywhere in Windsor-Essex, with a written quote the same day. One-year warranty, fully insured and WSIB covered. Call or text 519-567-4724.
