White grubs are the larval stage of beetles. According to Lee Townsend of the University of Kentucky, the white grub may become more prevalent during times of drought, when irrigated lawns present a green oasis for the beetles to lay eggs. After the eggs have hatched, the larval grubs will feast on the roots of most grass species. The white grub predators, skunks and birds, will then dig and eat the juicy bugs. Insecticides may be the best way to get rid of white grubs.
Apply either trichlorfon or carbaryl to the lawn where grub activity has caused problems. Problem areas may show up as brown patches in the lawn or green areas where the grass will pull up from the soil when grabbed by the green blades. These are areas where the grubs have eaten the majority of the roots so the grass will easily pull from the soil.
Follow the manufacturer's application instructions when applying the insecticide. In most cases, the trichlorfon and carbaryl will come either in a liquid or granular form. Mix the liquid insecticide in the sprayer, according to the label. Spray on the affected areas.
Broadcast the granular insecticide at the correct setting on the broadcast unit. Do not over-apply the insecticide. Irrigate the granular application with water from a garden hose and sprinkler attachment. Apply only the recommended amounts of irrigation to the lawn so chemical runoff does not occur.