Rationale White grubs (e.g. larvae of Japanese beetles or masked chafers) are the most destructive and economically injurious pests of turfgrasses in the Midwest and eastern United States. Developing grubs feed on turfgrass roots at the soil/thatch interface or in the first few centimeters of soil. Visual evidence of an infestation includes thinning, wilting in the presence of adequate irrigation, and yellowing or browning of the grass. Grub infestations typically occur in sporadic patches affecting only a relatively small fraction of the turfgrass in an area. The patchy nature of white grub infestations is rarely taken into account when managing these pests because of the difficulty of pinpointing the location and extent of infestation using traditional sampling techniques.