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Lawn Damage Due to Grubs & Rodents

Grubs are a common pest of turf grass lawns. There are more than 40 species of insects that have a "grub worm" larval stage. Grubs can directly damage your grass because they feed on the root system, but they can also harm it another way. Grubs attract rodents that feed on these grub worms, which can cause further damage.
  1. Process

    • Insects, such as beetles, are attracted to warm, moist soil. They deposit their eggs in the topsoil, right under the thatch. Moist soil is easy for these insects to dig in and it keeps their eggs moist and healthy. The female will burrow in the soil and lay a few eggs. She will repeat this cycle until she lays anywhere from 40 to 60 eggs. These eggs stay in the soil throughout the fall and winter. In the early spring, the eggs will hatch and the grub will live in the soil as it grows.


    • Grubs vary in size from ¾ to 1 ½ inches. They can be white, gray or brown. White grubs are the most damaging turf insect in the United States. According to the U.S. Department of Agriculture, Japanese beetle grubs alone cause $234 million in damage each year.


    • Grubs can stay in the soil for several months, depending on the species of insect. They feed on the root system of the grass, which causes the grass to die. Grub damage appears as dead, burnt patches in the lawn. Damage usually appears over a period of months.


    • Grubs not only cause surface damage to grass and plants, but they can attract rodents that can further damage the grass. Grubs usually stay close to the surface, just under the thatch. Rodents such as mice, moles, squirrels and gophers all feed on grubs. They will dig into the surface of the soil to locate the grubs. Moles, on the other hand, will dig tunnels below the thatch to capture grubs. This destroys the lawn even further. The best way to get rid of these rodents is to remove their food source and eliminate the grubs.


    • Once a lawn is damaged from grubs, the lawn will not recover. This is because the roots are dead. The grubs must be removed before the lawn is repaired. Simply reseeding a lawn will not be sufficient. The grubs will destroy the new grass.