In order to control grubs, you must understand their life cycle and apply the right product at the right time. In spring, adult grubs from the previous year begin moving to the surface as the temperature rises.
As they reach the surface, skunks and crows may try to dig them up. Any damage to the lawn at this point is from the skunk or crow rather than the grubs. If the skunks are destroying a large area of the lawn, apply a DYLOX product such as Bayer 24 Hour Grub Control. DYLOX is a fast-acting product that needs to be watered in well (1” water). It lasts about 2-3 weeks.
In summer months (late June/July), adult grubs pupate into beetles. These beetles lay thousands of eggs beginning in late July through September. When the eggs hatch, hungry grubs account for the most lawn damage in August through September and sometimes into October if temperatures remain warm.
To control grub population, you need to apply a season-long control that contains MERIT such as Bayer Season Long Grub Control. MERIT is a slow-acting systemic that takes about a month to start working but will last 3-4 months. For best results, the MERIT product must be applied in early June before the adult grubs pupate. Be sure that the product is watered in well. If it’s too late to apply MERIT, a DYLOX product can also be applied later in the season. MERIT and DYLOX don’t interfere with grass seed germination, so they can be used while seeding.