Count the grubs in the exposed soil. Replace the strip of sod. Following the same procedure, cut strips of sod in several other parts of the lawn and count grubs under each strip. Calculate the average number of grubs per square foot of lawn by dividing the total number of grubs by the number of strips. If the average number lies between 5 to 10 grubs in non-irrigated turf or greater than 20 grubs in highly maintained, irrigated turf, control measures may be required.
Adults feed above ground and deposit eggs in the stems of host grasses.
Zoysiagrass and bermudagrass are most often injured, but, feeding may occur on many grasses. In heavy infestations, roots of grass are destroyed and the turf killed in irregular patches. Damage from billbugs differs from white grub or mole cricket injured turf as infested soil usually stays firm. The nymph is ivory-colored with a brown head. Nymphs hatch in about two weeks and begin to feed immediately by sucking juices from the grass.