White grubs continue to be the most common turfgrass insect pest reported by homeowners. White grubs are the larvae of beetles and chafers. They may be found below ground among the roots of turfgrasses. The grubs are C-shaped, off white in color with a brownish head. One year is required by most species to complete their development, but some may take as long as three years.
Damage occurs throughout the summer.
Grubs chew off grass roots, and the lawn turns brown and dies. Check for grubs by digging a square foot of turf three inches deep - gradually pull apart over a piece of cardboard and look at the soil. If there are more than 8 grubs per square foot, treatment may be necessary. Control of various white grubs has become increasingly difficult since the loss of persistent chlorinated hydrocarbon insecticides. Rule of thumb is that if there are more than 8 grubs per square foot, soil should be treated.