- Use products containing trichlorfon or carbaryl from March to May 15 to kill grubs as they come closer to the ground's surface after wintering down deeper in the soil. After you've applied products containing either one of these compounds, the lawn will need water to saturate the product so it seeps into the soil. It can take up to 14 days for the grubs to begin dying.
- Products containing imidacloprid and halfenozide are preventive compounds. Products containing these compounds are applied to lawns during the first two weeks of July to control any grub larvae in the fall. These compounds will work to kill newly hatched grubs, but if they're applied later in the summer or early fall, the grubs are too large for the compound to harm them.
- Milky spore disease works to kill grub larvae of the Japanese beetle. The powder is applied to the grass and watered. Milky spore disease can be applied in the spring, late summer or fall to kill white grubs because the product works on all larval stages of the white grub. After the grubs ingest the milky spores, the disease slowly kills the grub. After the grub has died, it explodes, sending millions more spores into the ground for continuous protection from grub damage.
- Products containing permethrin, cyfluthrin, bifenthrin, gamma-cyhalothrin or lambda-cyhalothrin will not work for killing grubs. Products containing these compounds are meant to kill insects above ground and will not kill white grubs, which live 1 to 3 inches deep in the soil. The product binds with the grass blades and organic material, which prevents it from moving deep enough into the ground to kill the grubs.