White Grubs and Turf
White grubs are the larvae of beetles. The body of a grub is white with a brown head and a dark area on the rear abdomen. They have three pairs of legs that sit near the head of the body. When they rest, they rest in a C shaped position. White grubs have a life cycle ranging between 1 and 4 years. The first signs of infestation resemble drought conditions.
Signs of White Grub Turf Infestation
Thin, yellowing grass that feels soft and spongy are a definite sign of a white grub infestation. White grubs feed on grass roots. Infested turf develops irregular shaped brown patches scattered throughout the turf that grow larger over time. The grubs injure the turf roots nad that reduces the ability of the turf to take up water and nutrients, and weakens the turf's drought resistance. Badly infested grass pulls up very easily.
In addition, white grubs attract other wildlife including moles, raccoons, armadillos, and birds, which can make an already damaged area look worse. Large numbers of dark-colored, parasitic wasps with yellowish to white stripes on their abdomens that hover over the lawn on sunny days in the summer or fall may also be a sign of infestation. Sample the area to confirm that a white grub problem really exists.
In order to confirm you have a grub infestation, get a shovel, dig down a bit into the area you think is infested and sift through the top 3 inches of soil, roots, and thatch. You are looking for creamy-white, C-shaped beetle larvae. The larvae have tan to rusty-brown heads and six legs. Larvae that look like grubs but lack legs are probably billbugs. Adult grubs can vary in length from ¼ to 2 inches. Adults are needed for an accurate species identification. After examining the soil, replace the grass and water it. It is not uncommon to find an occasional grub and one or two grubs is not a problem. Healthy turf usually outgrows the root loss caused by a couple of grubs.
If your lawn is infested Professional lawn spraying is the best solution for controlling white grubs. Check with your local County Extension Agent for specific insecticide recommendations.