What do they do?
Grubs (larvae) such as the June Beetle or European Chafer feed on the roots of grasses in the lawn, leading to death of the grass and creation of bare spots, most evident in early spring when lawns "green up."
What does the larvae and adult look like?
The larvae are approximately 2 to 4 cm long with a soft, white "C" shaped body. There are slight differences between the different types of grubs, but they all have the same impact on grass roots. Grubs are usually found in the soil, near the edge of bare spots in the lawn.
Adults appear in early June until mid-July, and are about 3 cm long. These brown beetles usually swarm at dawn and dusk around trees and chimneys. Typically the European chafer is attracted to light, finding their way into homes through chimneys and open windows.
When is the damage to lawns at its greatest?
Eggs hatch in late summer and the larvae (Grubs) start feeding on the roots of grasses. If there are many larvae in a small area, the damage from feeding becomes apparent the following spring. As grubs grow they also feed on more roots, creating bare spots in lawns.
What can I do to assist my lawn if this insect is present?
If you are able to catch the adults and dispose of them, you can help reduce the mating population.
A spring and/or fall application of beneficial nematodes is an natural, organic way to treat and prevent grub infestation in your lawn. Nematodes are microscopic worms that parasitize larvae and are available in the refrigerated section of nurseries. Nematodes must be mixed with water in order to be applied to the grass. Follow product instructions for best results. Note: Nematodes have an expiration date and must be refrigerated until used.
If lawn damage has been done by the insect, restoration of the affected area in late May or early June can help re-establish growth of your lawn. Topsoiling, overseeding or sodding is the preferred method.
For more information, contact the Natural Environment Section via e-mail at firstname.lastname@example.org.