If you have the number you suggest why not go for direct assault on them. Spray your lawn with diazinon or Solgard ...et al. The grubs are feeding now from the eggs that were produced last June and now the full grown beetles are eating their way through lawns and will, in a short time, stop eating and dig their way down into the soil to spend the winter. They then return in the spring to take up where they left off. We've got 'snowbirds', now we have 'snowbugs'. Its too late for nemotodes to work effectively--probably cant find them anyway...they are a living organisms. Best time for this attack is July/August/September when the grubs are close to the surface. Heck, if you can see them, you can pick them up and drop into a soapy solution. Or spray with the insecticide. The next best time is in early spring when the grubs are once again near the surface; having come up from their winter quarters. They are probably too larger than when they went south. You might too, next spring, look for any parasites that feed on grubs. Wasps....they wont sting you, if you see them hovering over the soil surface are probably looking for grubs. Ground beetles and ants can also be helpful in controlling grubs. A good lush, healthy lawn is still one of the best defenses against invading grubs. Watered regularly, fertilzied regularly, cut at the proper height and leaving the clippings on the lawn can make for a great looking lawn. Good water retention in the fall can also make for a stronger turf to go into winter. Early snow-melt with rain can often make it better for lawns in spring.

There are several members of the Scarab Beetle family, japanese Beetles are one, that lay eggs in the soil that become these "C" shaped grubs we are all taught to hate with a passion. Research at several universities has found that if the population of the grubs is around 10 per square foot you can have a problem but that fewer then 5 per square foot are not. The adult beetles lay the eggs in July and August and they hatch and are then very susceptible to Milky Spore Disease, "Bacillus popilleae" which they must ingest as they feed. As the soil cools these grubs will move down further into the soil for the winter and they stop feeding, but in the spring, as the soil warms, they come back toward the surface to feed for a short time before they pupate to become the adult beeltes. Milky Spore Disease is effective, for a short time during the early stages of these grubs life, shortly after they hatch so it should be applied in early August, at the latest. Milky Spore Disease is also a very passive means of control. You put it down and then hope the grubs find it and ingest it, which is why those that need immediate gratification find it not vey effective. Beneficial nematodes, which eat the grubs can be applied about the same time or a little later. GrubX is not an acceptable organic solution because it is a broad spectrum poison that will kill many of the soil insects, both beneficial and harmful.

Grubs are a problem in in the summer heat (typically July). Are you saying you are just now getting around to treating for the problem you had back then? Have you dug up some of your yard and found active grubs? As a rule of thumb, we have talked in this forum for 15 years or more about grubs not being a problem if you have fewer than a dozen in a square foot. But if you dig up a square foot and find an uncountable mass of grubs, then you have a problem and should treat for it. If your lawn died back in July and you can find no grubs, then something else is going on and treating for grubs is a waste of insecticide/nematodes. If you decide to treat with nematodes, remember this: they must be applied with massive amounts of water. Nematodes only mode of transportation is via wetness.

Thank you all for your suggestions. We looked a the links provided and now just have to wait till it stops snowing and someone to turn up the temperature, so that we can see what kind of grubs we actually have... we are hopeful that maybe now that the grass is gone in the vegetable bed that the grubs have either died or moved. But, once there will be new plants, it will be a new story. However, the grass for the other garden bed( designated for mostly flowers but also some vegetables ) has only been turned upside down, and new garden soil was put on top. And we also saw rabbit tracks in the snow, which means we also need to consider building an enclosure. Ah, the fun of gardening, and we have not even started yet...