UGA Extension Office

November 2017

Expanding dead zones in your lawn? You may have white grubs

Have you noticed expanding brown areas in your lawn that rolls up like a carpet, as if the turf has no roots? That’s because it may not. Many people in Hart County and Northeast Georgia have noticed the effects of white grubs in their lawns recently, and may be wondering what they are and what they can do to control them.

White grubs are the immature stages of Scarab beetles, such as green June beetles, Japanese beetles, and chafers. These beetles lay eggs in your lawn in spring and the larvae feed on turf roots through summer and fall. In the winter, they dig deeper into the soil and emerge as adult beetles the next spring. Though the adult beetles can be pests themselves, the grubs damage your lawn by feeding on the turf roots and prevent the plant from accessing water and nutrients. In addition to brown, loose areas of turf, many people notice additional damage in their lawn caused by birds, skunks, and armadillos digging for grubs to eat.

Most grubs never come to the surface, so the best way to determine if you have white grubs in your lawn is the dig them up. Near the boundary of healthy and damaged turf, cut three sides of a 1-foot square and then roll the grass back like a carpet. Use your hands to sift through the top few inches of soil to search for the grubs. Sample a few different areas if you don’t find anything on your first try. If this process makes you squeamish, call the Extension office for assistance.

Control of white grubs usually involves the use of an insecticide. Treatments are most effective when the grubs are small, mostly in June and July. In October, however, treatment options become limited and can be less effective as the grubs are larger. Insecticides containing the active ingredient trichlorfon provide the best control for older larvae, such as Bayer Advanced for homeowners or Dylox for those with a Pesticide Applicators license. When applying insecticides for white grubs, irrigate beforehand to bring the grubs near the soil surface and again after application to move the chemicals down into the soil.

Published on November 9, 2017 in The Hartwell Sun

White grub