Grubs in the lawn

The grub is the larvae stage of a variety of beetles. Japanese beetle, European chafer and June beetle are the most common three. European chafer is the worst for destroying lawns in our area.

Damage and I.D.
Grubs feed on grass roots causing your lawn to die. The key symptom of grub invasion is irregular deed patches which will lift up easily if tugged on These patches have had the roots severed and there is nothing to anchor the sod in place. The lawn may also have patches that have been burrowed in or been up-turned by moles, skunks or raccoons feeding on grubs. The highest concentration of grubs will be found in dead turf bordering green areas. The grub is 'C' shaped with a brown head, white body and six legs on its upper half.

Grubs were first imported from the Orient in their adult stage and first discovered in North America in New York.

Life cycle
The grub's life cycle is very simple. The grub feeds on grass roots from mid-March to mid-May, and then develops 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. The grubs will burrow below the frost line in the fall and stop feeding but 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.

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

For details on how to keep your lawn healthy, visit Health Canada's Healthy Lawn website.