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IdentificationLow risk

What Are Curl Grubs?

Written by PestMan Editorial TeamTechnical review pendingPublished Updated

Quick answer

Curl grubs are the C-shaped, creamy-white larvae of scarab beetles, including the African black beetle. They live in the soil and eat grass roots, so turf turns brown, stops responding to water and lifts away like loose carpet. Birds and bandicoots digging in the lawn are often the first sign. Damage is usually worst from late summer into autumn.

Why this happens

Adult beetles lay eggs in lawns and garden beds in late spring and summer. The curl grubs that hatch feed on roots and organic matter through summer and autumn.

With fewer roots, grass can’t take up water, so patches dry out even after watering. Animals that eat grubs dig and peck the lawn, adding to the damage.

What you may be seeing

  • Brown patches where turf peels back easily.
  • C-shaped white grubs with brown heads in the top 5–10 cm of soil.
  • Birds, bandicoots or foxes digging holes in the lawn.
  • Shiny black beetles at outdoor lights or in pools (African black beetle).

What you can do

  • Lift a few squares of turf in damaged areas and count grubs; small numbers may not need treatment.
  • If grubs are numerous, use a product registered for curl grubs in turf, following the label, and water it in as directed.
  • Encourage deep roots with less frequent, deeper watering.

What not to do

  • Do not treat without checking for grubs first.
Using pest products safely

If you use any insecticide, bait or trap, read the label first and follow it exactly. Australian law requires products to be used only as the label directs, including around food, children and pets.

When professional help may be needed

Lawn care professionals can confirm grub numbers and time treatment for when young larvae are feeding.

Lawn Pests

Caterpillars and beetle larvae that eat grass leaves or roots, leaving brown, dying patches. Armyworm and curl grubs cause most lawn damage in eastern Australia, especially in warm, humid months.

Species mentioned

Curl Grubs

Scarab beetle larvae (Scarabaeidae)

C-shaped, creamy-white beetle larvae that live in soil and eat grass roots, causing patches of turf that die and lift away like loose carpet.

African Black Beetle

Heteronychus arator

An introduced, shiny black scarab beetle whose larvae are a common type of curl grub. Adults also chew grass at the base and are drawn to lights.

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Sources & further reading

PestMan provides general information only and does not replace licensed pest-management, medical, veterinary or structural advice. Always read and follow product labels. Read our disclaimer.