On locating a grub, she stings and paralyzes it. She may burrow 1.2 cm deeper to construct a cell around the host. Then she lays an egg on the outside of the grub. The parasitized larva provides a fresh food supply for the wasp larva. The stung grubs never recover.
Many grubs are stung, but only a few eggs are laid.
These wasps, therefore, are very important natural agents in the control of grubs in the soil. Since these beneficial insects rarely, if ever, sting people no control measures are needed. Their presence, however, means there is a green June beetle, Japanese beetle or May beetle grub infestation that may be only partially controlled by these parasites. For recommended insecticides and rates, consult the stage agricultural extension service recommendations.