White grubs are major insect pests that feed on the roots of some turf. Quick detection, regular watering and treatment prevent extensive lawn damage.

Signs of trouble

Moles, skunks and birds feeding in the lawn are often the first sign of a potential grub problem. Grub damaged turf can typically be rolled back like a carpet because roots are no longer present. Control is recommended when more than eight grubs are found in a square foot area.

In July and August, when the lawn is under stress from heat and drought, yellow or brown areas appear, indicating loss of roots from feeding grubs.

What do white grubs look like?

Grubs are immature or larval stage of beetles such as the Japanese beetle, European chafer and Asiatic garden beetle. Most white grubs can be distinguished by their characteristic C-shape curl, whitish body and brown head. They measure 1/4 inch when young and extend to 2 inches when fully developed.

Control Strategies

Once the lifecycle of grubs is understood, it is easier to determine the time and method of control. Adult beetles lay eggs in mid-summer and deposit them a few inches below the soil in lawn and garden areas. In 2 weeks, young grubs hatch and develop into full-size grubs that feed on the roots below the soil surface. As soil temperatures drop in the fall, the grubs move deeper in the ground where they spend the winter.

In spring, as the soil warms up, the grubs move upward to begin feeding on roots. Adult beetles emerge, mate and lay eggs during the summer, thereby starting the cycle all over again. Research indicates that the best time for control is the young grub stage when they are actively feeding on roots.

Ways to control white grubs

Cultural Practices

Research indicates that healthy turf often counteracts grub damage to some extent.

1.        Plant the variety of turfgrass that is best suited to your growing conditions (soil, heat and lawn use) so it will not be under extra stress. Ask your Agway lawn expert for the improved mixes for your site.

2.        Water routinely during dry spells so turf is healthy and not drought stressed.

3.        Fertilize turf as recommended by soil test results.

Chemical Controls

Summer: If grub damage warrants control in summer (usually August when young grubs are feeding on grass roots) see your local Agway store for recommendations. 

Spring: is also a good time to apply grub control. Milky Spore is an excellent long-term solution that will not harm pets, children or ground water supplies. It should be applied before grubs hatch in early spring. Treat your lawn with the products indicated above if hatched grubs are near the soil surface.