1-Keep your lawn healthy, fertilize and mulch. Don’t mow too short.
2-Aerate. Beetles prefer compact undisturbed soil to lay their eggs.
Nematodes are a naturally occurring microscopic worm found around the globe. They hunt and feed on soil dwelling insects like grubs. You get approximately 10 million nematodes in an individual package which covers 2000-3000 square feet. Apply them by using a watering can, sprayer with hose attachment or misting. Apply them during low light periods (morning or early evenings are best). If possible you should water your lawn before applying or apply after a light rain for best penetration. Avoid soil temperatures below 10 C / 50 F.
IMPORTANT: There are two periods when grubs can be targeted by nematodes, in the Spring when soil temperatures are above 10 C (often May to early July) and again in the fall before the soil gets too cold (mid-late September to mid October).
4-Apply Diatomaceous Earth.
Diatomaceous Earth is an off white talc-like powder that is fossilized remains of marine phytoplankton. When sprinkled on a bug that has a exoskeleton it comprises their waxy coating. It is best applied in dry conditions (even morning dew can make it ineffective) with a salt shaker or a spray bottle mixed with water. It does not hurt mammals of humans.
IMPORTANT: Diatomaceous Earth kills ALL bugs with an exoskeleton (bed bugs, lady bugs, slugs, bees, spiders fleas, ect). This is not a bait or poison, must be applied to the bug.
5-Change your lawn to a Grub/Beetle resistant grass seed like Tall Fescue, Red Fescue or Micro Clover