Grub Problem in Lawn
Some, but not all, grubs can be controlled with beneficial nematodes. As with all integrated pest management (IPM) methods, you need to be willing to accept something less than a complete kill. The nematodes are delivered alive and they will need careful handling to keep them alive. Instructions must be followed to the letter. If insecticides have drifted from other plants to your lawn the nematodes may die before they can infect the grubs.
A good, unbiased discussion is at: http://ento.psu.edu/extension/factsheets/white-grubs-lawns