---
title: Curl Grub
canonical: https://fernland.com.au/problem-solver/curl-grub/
dateModified: 2026-08-07 09:44:55
summary: "Curl grubs are C-shaped scarab beetle larvae that feed on turf and pasture roots, causing patchy, spongy dead areas that lift easily."
type: article
keywords: [Curl Grub, Scarabaeidae]
---

# Curl Grub

> Curl grubs are C-shaped scarab beetle larvae that feed on turf and pasture roots, causing patchy, spongy dead areas that lift easily.

*Scarabaeidae*

Curl grub is the common name for the soil-dwelling larval stage of scarab beetles (family Scarabaeidae), a group that includes African black beetle, Argentine scarab, billbugs and various cockchafers. Several genera occur in Australian turf and pasture systems, and while the adults differ in size and colour, the larvae share a similar appearance and cause similar root damage.

The larvae are cream to greyish-white, soft-bodied grubs with a distinctly curved, C-shaped posture, a darker brown head capsule, and three pairs of small legs near the front of the body. Depending on species and age they range from around 10 mm to 30 mm long. They live in the soil profile just beneath the turf or pasture, feeding on roots, organic matter and thatch. Adult beetles are hard-shelled, dark brown to black, oval to rounded in shape and usually 8-20 mm long; they fly at night, particularly after rain in warmer months, and are often attracted to lights.

Curl grubs are present across most of Australia's turf-growing regions, with populations building through spring and summer as adult beetles lay eggs in soil. Larvae feed through the warmer months and cause the most visible damage in late summer and autumn, then move deeper in the soil profile to overwinter before pupating and emerging as adults the following season.

Management relies on monitoring turf regularly, since damage often appears only after populations have built up. Maintaining healthy, deep-rooted turf through good irrigation and fertility practices helps it withstand low-level feeding, and reducing excess thatch can make conditions less favourable for grubs to establish. Biological controls, including certain nematodes and fungal pathogens, and targeted insecticide applications timed to when larvae are small and actively feeding near the surface, are the main control options; timing is critical as larger, deeper-dwelling grubs are harder to control.

## How to identify

- **Patchy, irregular dead or dying turf** that may feel spongy or soft underfoot, often first noticed in late summer or autumn.
- **Turf lifts away easily** from the soil in affected patches because the root system has been eaten away, sometimes rolling back like a loose carpet.
- **Increased bird or animal activity** (magpies, ibis, foxes) digging or pecking at the turf surface, attracted by the grubs.
- **Weakened turf** that wilts under heat or drought stress more readily than surrounding healthy areas, even with adequate irrigation.**Field check:** Cut and peel back a section of turf at the edge of a damaged patch and inspect the top 50-100 mm of soil. Count the number of C-shaped grubs found per square metre or spade square; higher numbers indicate a population likely to cause ongoing damage, though thresholds vary by grass species and grub type.

**Lookalikes:** Curl grub damage can resemble *African black beetle* damage, since black beetle larvae are also curl grubs — the adult beetle stage is the easier way to distinguish species. Damage can also be confused with *drought stress* or *fungal disease* patches; unlike disease, curl grub-affected turf typically lifts freely from the soil due to root loss, and digging will reveal the grubs themselves, confirming the cause.

## Registered products we stock

- [Eco-Neem Botanical Insecticide](https://fernland.com.au/eco-neem-botanical-insecticide/) — Organic Crop Protectants

## Image credits

- [Photo: division, CSIRO via Wikimedia Commons (CC BY 3.0)](https://commons.wikimedia.org/wiki/File:CSIRO_ScienceImage_2200_A_Curl_Grub_larvae.jpg)
- [Photo: Toby Hudson via Wikimedia Commons (CC BY-SA 3.0)](https://commons.wikimedia.org/wiki/File:Curl_grub.jpg)