** Answer ** The appropriate intervention at this time is to apply a granular organophosphate insecticide such as Dursban®, Dylox®, or Diazinon®. Follow label directions carefully and water these products down into the soil where the grubs live thoroughly with a half inch of water. These insecticides possess a fairly short window of effectiveness, breaking down within 2-3 weeks after application, making application timing critical! As a general rule of thumb, best control with the above products is often had when applied from late-July to mid-August in the transition zone. This does not mean that you will be guaranteed success if you treat in late July. I have found that treatments using the above products are effective through mid- September. You must inspect your lawn to determine if and when grubs are present; depending on preceding year's weather, they may be present earlier or later than when generally predicted. Other concerns with the use of organophosphate insecticides are that as a group they are generally the most toxic of all turfgrass pesticides to humans and other animals; they are also highly toxic to earthworms, birds, and honeybees. Fortunately, homeowners now have two new grub control insecticide options that are the safest of all turfgrass insecticides to humans and other animals and are also relatively non-toxic to earthworms, birds, and honeybees: Merit® (imidacloprid) and Mach 2® (fluvalinate). Merit® is a recently developed synthetic insecticide whose mode of action (i.e., how it kills) resembles that of the natural botanical product, nicotine. Mach 2® is a recently developed molt accelerating compound that mimics the action of the insect molting hormone, ecdysone. Ingestion of even a minute amount of Mach 2® causes grubs and caterpillars to attempt a premature, lethal molt. In addition to their added safety, these two new insecticides also last a long time in the soil (6-10 weeks) before breaking down and becoming ineffective. These products, therefore, can and should be applied preventively, prior to grub egg hatch. Merit® or Mach 2® should be applied in mid- to late-June and watered in. They are available in most hardware and garden centers in bags alone or together with fertilizer granules. Use of the insecticides without added fertilizer is preferred due to the fact that lawns should not be fertilized in the summer or disease may be promoted. Treating the lawn as soon as possible will certainly increase the possibility of any further damage. I would advise checking other sections of lawn to determine the extent of the grub infestation. A second treatment may be necessary this season before you can gain control over the problem. As far as re-seeding or sod this fall, you may do either there is still time this growing season to re-establish the damaged areas using seed, just remember to use a layer of straw over the bare or browned out sections to aid in keeping your new seed moist. Sod will provide the instant repair of the damaged areas without waiting for seed to germinate, either method is fine now or in the spring. Thanks for The Question !