The Japanese beetle, Popillia japonica Newman, is a major pest of turfgrasses and woody landscape plants in the eastern United States. Imidacloprid, a long residual chloronicotinyl soil insecticide, is widely used for preventive control of root-feeding Japanese beetle grubs and other scarabaeids in turfgrasses. Preventive control is assumed to result from the residues killing neonate larvae, however, little is known about whether it also may involve sublethal effects on ovipositional behavior or larval feeding, or reduction in egg viability. Female Japanese beetles alight upon turf and burrow down through thatch and soil when laying eggs. We tested if females avoid treated turf, or if they become intoxicated in the upper soil, thereby reducing their egg-laying and subsequent ability to disperse and feed. We also tested whether imidacloprid residues prevent egg hatch either by intoxicating the embryo or poisoning the hatchling as it consumes the chorion. Finally, we studied if imidacloprid reduces feeding by late instars. Our results clarify the process by which imidacloprid and possibly other chloronicotinyls accomplish preventive control of scarabaeid grubs.