Improve Lawn’s Soil
The best way to eliminate grubs under the lawn is to improve the soil there so that natural predators such as ants and ground spiders thrive and eat the eggs and larvae. Create a rich environment for them by adding organic matter to the soil and aerating it to provide the air and nutrients they need. Topdress the lawn with organic material such as peat moss, compost, topsoil or a mulch of leaves shredded while mowing with a mulching mower. A bonus is grass roots that penetrate deeper and plants that are healthier and better able to withstand grub attacks.

Increase Plant Diversity
Grubs are normal citizens in a healthy landscape. They and the beetles have a role in your ecosystem. Having some grubs is not a problem. Having too many grubs in one place is the problem. An overpopulation of grubs is generally a sign that the natural predators in your yard are not able to keep after them and the beetle population has exploded

Encourage populations of the many predators living in your yard that normally control these pests by planting plants that they need for food and shelter. Besides other insects grub and beetle predators are rodents, amphibians and birds. The greater the variety of trees, shrubs and decorative plants on your property, the better it can support a diversity of natural grub and beetle enemies.

Control Grubs By Spiking
White grubs feed nearest the surface of the soil in late spring and again in August and September. That is the time when you can kill many of them with some form of spiking tool that has sharp tines at least 2 inches long. Golf shoes do not do the job, but special shoes with spikes attached to the bottom are now available. You can also purchase a hand spiking tool that does a good job. The more spike holes in the turf the more grubs killed and the better your soil. Research shows that turf that is spiked frequently contains about half as many live grubs, and grows stronger plant root systems because the spiking aerates the soil. In planting beds, prior to planting dig into the soil a few inches and turn over shovelsful to surface grubs for birds to eat.