Beetle Grub Infestation in a Garden

Red Flat Bark Beetle Larvae (Katja Schulz via Wikimedia Commons, CC BY 2.0)

Beetle grubs are the larvae of several species of beetles, including June beetles and Japanese beetles. These pests can cause serious damage to lawns and gardens by feeding on the roots of plants and grasses. A beetle grub infestation can result in brown, dying patches of lawn or wilted, stunted, or dead plants.


  • Brown, circular patches of dead grass in lawns
  • Wilting or stunted growth of plants, especially near the edges of affected areas
  • Roots of affected plants easily pulled out of the ground
  • Presence of visible grubs in soil or on the surface of the lawn
  • Presence of animals such as moles, skunks, or birds digging in the lawn or garden, as they are attracted to the grubs as a food source.
  • Increased numbers of adult beetles seen around affected areas
  • Root systems of affected plants that appear stunted or missing altogether
  • Soil that appears to be heavily compacted or matted, due to grub feeding and burrowing behavior.

What is a Beetle Grub

  • C-shaped body with a curved appearance
  • Typically white or cream-colored with a brown head
  • Usually around 1 inch to 1.5 inches in length
  • Legless with a soft, plump body
  • Often found in soil near plant roots
  • May have small spines or tufts of hair on their body.

Treating a Beetle Grub Infestation

It may be necessary to use multiple methods for the most effective treatment of a beetle grub infestation. For example, chemical control may provide quick results, while biological and cultural control methods take longer but are a more sustainable solution.

Chemical Control

  • Apply insecticides containing neonicotinoids or carbamates to the soil. Products containing imidacloprid, clothianidin, or thiamethoxam are examples of neonicotinoids. Products containing carbaryl or bendiocarb are examples of carbamates
  • Apply in late summer or early fall when grubs are actively feeding
  • Water in well after application
  • Follow all safety precautions and label instructions.

Biological Control

  • Introduce natural predators such as birds, skunks, and hedgehogs to the garden
  • Provide a habitat for predators, such as birdhouses or hedgehog shelters
  • Avoid using chemical insecticides that may harm beneficial insects or animals.

Cultural Control

  • Remove and destroy any affected plant material
  • Aerate the soil to encourage healthy root growth
  • Maintain a thick and healthy lawn to reduce grub damage
  • Reduce irrigation to encourage deeper root growth and drought tolerance
  • Rotate crops to reduce pest build-up.

Physical Control

  • Handpick grubs and remove them from the soil
  • Use a shovel or garden fork to disturb the soil and expose grubs to natural predators
  • Apply nematodes, microscopic worms that feed on grubs, to the soil