white grubs

Grubs in Your Lawn

What are White Grubs?

White grubs are the slug-like larval stage of many insects. They they live just below the surface in topsoil, eating the roots of grass and other plants as they grow. It’s not uncommon for a single lawn to host hundreds of grubs, which devour the roots of turf grass and leave unsightly brown spots. As the infestation progresses, an entire lawn may be destroyed.

The most commonly encountered white grubs are the larvae of June bugs, European Chafers, Masked Chafers, Billbugs, Oriental Beetles and Japanese Beetles. All of these species start as soft-bodied grubs, and are practically indistinguishable from one another. They are white-colored, C-shaped and often have small legs and tiny heads. Most are between a ½ inch and 2 inches long.

Life cycle

The grub’s life cycle is very simple. They feed on grass roots from mid-March to mid-May, developing into its pupal form. The adult beetle then emerges in mid-June, mates over a two week span and retreats back into soil to lay its eggs. The grubs hatch and begin to feed in late July to August. They will burrow below the frost line in the fall and stop feeding. If there is a thaw, they will resume feeding at any time, even during the winter. The grubs will continue to feed in the spring, constantly growing larger.

Signs of White Grub Damage

bird feeding on gribs

One of the first signs of a grub problem is an influx of birds (starlings, crows, flickers, blackbirds) to the infested area. Animals can further damage the lawn or garden because they dig up the areas where grub scents are the strongest. A number of animals may be responsible for this damage, including raccoons, opossums and moles. Nighttime visits by skunks to your property is another indicator of a white grub infestation. Dead spots on the lawn is another giveaway, and in these areas the grass will turn brown and die. This is the result of the grubs eating away at the roots, killing the grass. As the grubs move around and feed, a large section of the lawn will become so damaged that the grass easily pulls away in large chunks. Affected areas will feel soft and spongy to walk on.

Grubs can also cause serious trouble in gardens, particularly rose gardens.

White Grubs do the most damage August through October when they are feeding and growing. Less damage is done at other times of the year.

Let nature control the grub population!

Nematodes are earth-friendly microscopic worms which feed on the backs of white grubs until they are eradicated. Nematodes occur naturally in your yard, busy eating away under the surface of the soil, doing their work on grubs and certain other soil born insects including cinch bugs. When you apply nematodes in their dormant state you are intensifying their population in an effort to bring your grub problem under control.

Nematodes are best applied to your lawn when the soil has warmed up, but is moist. From early to mid August on, keep an eye on the lawn for damage. Nematodes can be applied at this time of year as an effective treatment for grubs. Once the Nematodes have been applied, they will move quickly through the pre-moistened soil. Keep your lawn moist during the summer as the Nematodes require a film of water in which to move and infect target insects. The Nematodes will survive for up to 15 months. A fresh application will be needed following that.

Keep applying Nematodes for 2-3 years until you are confident your lawn is grub free. Regular applications of fertilizer will keep your grass strong and increase root production. Minimize thatch build-up so that fertilizer, water, and air can pass into the root zone easily. Keep your lawn well watered with 1″ – 1.5″ of water per week. If your life is too hectic, consider installing an irrigation system so you can set a timer for regular intervals.

The secret to successful grub control

Water your lawn for 2 hours before you applying the dormant nematodes and again for 2 hours afterwards. The nematodes will multiply on contact with water and are driven deep into the soil where the grubs live.

A well maintained, well watered and well fertilized lawn may have grub problems but because it is so vigorous, more roots will grow as they are destroyed. You may not even detect a problem. If you do, the damage will not be as severe.

For details on keeping your lawn healthy, visit Health Canada’s Healthy Lawn website.

Leave it to the “Professionals”

Don’t have the time or the know-how? Not to worry. Twisted Oak Landscaping can can arrange to have your lawn and gardens treated for white grubs the environmentally  friendly way.


Need more info?

If you notice any of these issues in your lawn, make sure to check for white grubs.
Got grubs? Give us a call at 647-881-2980 or request a consultation.