Unfortunately, there is no way to eliminate Japanese beetles in your yard if they are present in the surrounding area. The best that you can do is to make your yard uninviting to them by planting herbs like tansy, catnip, garlic and chives which will repel most of the beetles. If you don't want to apply soap, milky spore or parasitic nematodes to your lawn, try inviting birds into your yard by providing a water source such as a birdbath and trees and shrubs for them to perch and build their nests in. Birds like robins love grubs. I've even seen woodpeckers digging for grubs in my yard.