Grubs are the larvae of insects, such as Japanese and Oriental beetles, that reside underneath your lawn and feed on the grass roots. While some grubs are tolerated in a landscape, too many larvae in one spot can cause browning of grass and bare patches of lawn. Apply lime to your own lawn to pave the way for healthy grass and fight off grubs.
Cut out a 6-by-6 inch section of your lawn with a flat spade to identify the number of grubs found in the top 3 inches of soil. Repeat this process in at least a dozen other areas to locate the trouble spots. More than three grubs in a sample indicates that the area needs to be treated.
Scoop small spoonfuls of dirt from various areas of your lawn and place them in different plastic bags to test the soil's pH. Follow the kit's directions for processing the samples and getting the results. This reading helps determine how much lime to use so that you do not damage your grass with an over application.
Pour pelletized lime in a drop or spinner spreader and apply it to the infested areas that you identified in Step 1. Do not overlap the lime so that you do not inadvertently cause the pH to be higher in one spot. For best results, do this in the fall, between August 1 to September 15, before the grubs have a chance to feed on the nutrients of your lawn. Follow the instructions on the package for information on reapplication.
Repeat Step 1 on a yearly basis to ensure that the lime is reducing grub numbers.