Lawn Care: Is Grub Control Necessary?

There are ways to determine when grub control is necessary.

Lawn grubs can do severe damage to a lawn, causing the turf to turn brown and die. The simple presence of lawn grubs, however, does not mean control is necessary.

White Grub Description

White grubs are the larvae of beetles. They are C-shaped, off-white in color and have a brownish or tan head. They are generally 1/4 inch to 3/4 inch in length. Grubs damage lawns by chewing off the roots of the grass.

Assessing Damage

Signs of lawn grub damage include patches of brown, dying grass. You can dig up a square foot of turf 3 inches deep and then pull it apart over a piece of cardboard or paper to look for grubs. If there are more than eight grubs per square foot, consider taking measures to control the grubs.

Control Methods

Cultural control methods include irrigating the lawn and fertilizing appropriately. High-nitrogen fertilizer, for instance, can be detrimental, and weaken the grass, making it more susceptible to grubs; you should avoid it. Damaged lawns can be re-seeded. Apply chemical controls only in extreme cases.

References

• University of California IPM: Lawn Insect Management Guidelines
• Cornell Cooperative Extension: Lawn Insects: White Grub
• Michigan State University: Integrated Pest Management for Home Lawns