31 Jul The Ultimate Guide To Lawn Grubs In Australia
Noticing unexplained brown patches, thinning grass or birds suddenly taking an unusual interest in your lawn? Lawn grubs could be responsible, but identifying the problem before treating it is important. Many lawn problems can look similar at first, and what Australians commonly call a “lawn grub” can refer to more than one type of turf pest.
Curl grubs and armyworms, for example, are very different. Curl grubs are beetle larvae found beneath the turf, while armyworms are caterpillars—the larval stage of moths—that feed primarily on grass foliage. Knowing what you’re dealing with can help you choose an appropriate treatment and avoid treating your lawn for a pest it doesn’t have.
In this guide, Australian Seed & Turf Farm explains how to identify common lawn grubs, recognise potential signs of an infestation, check your lawn, understand treatment and prevention options, and help damaged turf recover.
If you’re looking for more practical advice on keeping your turf healthy throughout the year, explore our broader lawn and turf articles.
What Are Lawn Grubs?
In brief: Lawn grubs are a broad term commonly used in Australia for insect larvae that can damage turf. Different pests may be described as lawn grubs, including curl grubs and armyworms, but they don’t all feed on the same parts of the grass or require the same management approach.
This distinction matters. A lawn that suddenly appears thin, yellow or brown doesn’t automatically have “grubs”, and even finding a larva doesn’t necessarily tell you how it is damaging your turf.
Curl grubs are the larval stage of certain beetles. They live below the surface, and some species can feed around the root zone, potentially weakening the connection between the turf and soil.
Armyworms are caterpillars and feed above ground, consuming grass foliage. In a significant outbreak, this feeding can make areas of turf appear rapidly thinned or stripped.
Understanding these differences is the first step towards identifying what’s happening in your lawn.
Lawn Grubs At A Glance
| Question | Quick Answer |
| What are lawn grubs? | A common term for several insect larvae associated with turf damage |
| Common examples | Curl grubs and armyworms |
| Where are curl grubs found? | Usually beneath the turf in the soil/root zone |
| Where are armyworms found? | Around the grass foliage, thatch and surface |
| What damage can occur? | Root damage, chewed foliage, thinning or brown turf depending on the pest |
| Can lawn grub damage be repaired? | Often, but recovery depends on the severity of the damage and condition of the remaining turf |
| Should every brown lawn be treated for grubs? | No. Brown turf has many possible causes, so identifying the problem first is important |
Seed & Turf Expert Tip: One of the most important steps is confirming that you’re actually dealing with a pest. Drought stress, uneven watering, disease, soil problems and nutrient deficiencies can all cause discolouration or thinning. Look for multiple signs rather than diagnosing lawn grubs from a brown patch alone.
What Do Lawn Grubs Look Like?
What a lawn grub looks like depends on the pest you’re dealing with. Curl grubs typically have pale bodies, brownish heads, and curl into a distinctive C-shape, while armyworms look like elongated caterpillars.
Because these pests can damage turf differently, appearance can provide an important clue when working out what is happening to your lawn.
What Do Curl Grubs Look Like?
Curl grubs are commonly recognised by their white to cream body, darker head and curled shape. When disturbed, they often form a C-shape.
You’ll generally find them below the turf rather than crawling openly across the grass. If you peel back a section of affected turf or inspect the soil beneath it, you may find larvae around the root zone.
However, finding a grub in the soil doesn’t automatically mean it is responsible for all the damage you’re seeing. Identification, numbers, symptoms and the overall condition of the lawn should be considered together.
What Do Armyworms Look Like?
Armyworms look very different from curl grubs because they are caterpillars rather than beetle larvae. Their appearance varies by species and stage of development, but they have elongated bodies and can show longitudinal stripes.
Armyworms feed on plant material rather than living exclusively around the root zone. They can be easier to spot when actively feeding, particularly around the lawn surface and base of the grass.
This difference gives you one of the first diagnostic clues:
C-shaped larvae beneath the turf → investigate curl grubs.
Caterpillar-like larvae associated with chewed foliage → investigate armyworms.
Curl Grubs Vs Armyworms: What’s The Difference?
Curl grubs and armyworms are sometimes grouped together under the term lawn grubs, but they are different pests with different lifecycles and feeding behaviours.
| Feature | Curl Grubs | Armyworms |
| What are they? | Beetle larvae | Moth larvae/caterpillars |
| Appearance | Pale, usually C-shaped, with a darker head | Elongated caterpillar, often with visible stripes |
| Typical location | Beneath turf around soil and roots | Turf surface, foliage and around the base of grass |
| Main area affected | Root zone for root-feeding species | Grass foliage |
| Potential damage | Weakening turf, root loss and brown areas | Chewed foliage, thinning and rapid loss of green leaf |
| Detection | Inspect soil beneath affected turf | Inspect grass and thatch, including around dusk/night |
| Treatment | Depends on species, lifecycle and infestation | Depends on species, lifecycle and active infestation |
The practical takeaway is simple: don’t assume every lawn grub should be treated the same way. Identifying the pest gives you a much stronger starting point for choosing an appropriate response.
What Are The Signs Of Lawn Grubs?
Possible signs of lawn grubs include yellow or brown patches, thinning grass, damaged roots or leaves, turf that pulls away from the soil more easily and increased feeding activity from birds. The exact symptoms depend on the pest and severity of the infestation.
Brown Or Yellow Patches
One of the first things people notice is often an area of lawn losing colour.
The affected area may initially look dry or stressed before becoming increasingly yellow or brown. However, discolouration alone isn’t enough to diagnose a grub problem; insufficient water, disease, heat stress and nutrient issues can create similar symptoms.
Turf That Pulls Up Easily
If a root-feeding pest has caused substantial damage beneath the lawn, the affected turf may lose some of its attachment to the soil.
Gently test the edge of a damaged area. Turf that lifts unusually easily warrants further investigation of the root zone underneath.
Chewed Or Missing Grass
Chewed foliage points towards a surface-feeding pest rather than a root problem.
With armyworms, feeding can remove green leaf material and make sections of lawn appear closely cut, thinned or stripped. In a significant outbreak, the visual deterioration can happen quickly.
Increased Bird Activity
Birds suddenly spending considerable time pecking or feeding in one section of your lawn can be a useful clue that insects are present.
It isn’t proof of lawn grubs, though. Birds feed on many insects and other organisms in turf, so combine this observation with an inspection of the affected grass and soil.
Seed & Turf Expert Tip: Don’t wait for the entire lawn to turn brown before investigating unexplained damage. Checking a problem while healthy and affected turf are both present can make it easier to compare the two areas and look for active pests.
Lawn Grubs Or Something Else?
Brown grass doesn’t necessarily mean lawn grubs. Before treating the lawn, consider other common causes of turf decline.
| What You Notice | Lawn Grubs | Drought / Water Stress | Lawn Disease | Nutrient / Soil Issue |
| Brown or yellow patches | Possible | Common | Common | Possible |
| Visible larvae | Strong supporting evidence | No | No | No |
| Chewed foliage | Possible depending on pest | No | Damage may look different | No |
| Damaged roots | Possible depending on pest | Severe stress can affect roots | Possible | Possible |
| Increased bird feeding | Possible clue | Not typically | Not typically | Not typically |
| Improvement after correcting irrigation | Not while active pest damage continues | Often | Variable | Variable |
The goal isn’t to diagnose every lawn condition yourself. It’s to establish whether there is enough evidence to suspect an active pest before applying a treatment.
How Do You Know If You Have Lawn Grubs?
To check for lawn grubs, inspect both the damaged turf and the soil underneath it, paying particular attention to the boundary between healthy and affected grass. What you’re looking for depends on whether you suspect a below-ground pest such as curl grubs or a foliage-feeding pest such as armyworms.
Start with the lawn itself. Look at how the damage is developing, whether leaves have been chewed and whether affected turf is firmly attached to the soil.
If you suspect curl grubs, carefully lift a small section around the edge of the affected area and inspect the soil and roots beneath it. Look for pale, C-shaped larvae and evidence that the root system has been compromised.
If the grass itself appears eaten, inspect the foliage, thatch layer and base of the turf. Checking around dusk or at night can sometimes make actively feeding caterpillars easier to detect.
Why Check The Edge Of The Damage?
The middle of a severely damaged patch tells you what has already happened.
The boundary between healthy and damaged turf can tell you what may be happening now.
If an active pest is moving through the lawn, inspecting that transition zone may give you a better chance of finding evidence than examining an area where little healthy grass remains.
What Causes Lawn Grubs?
Lawn grubs don’t simply appear because a lawn has been poorly maintained. They are stages in the lifecycles of insects already present in the surrounding environment.
Adult beetles associated with curl grubs can lay eggs that develop into larvae in the soil. Those larvae continue developing before pupating and eventually becoming adults.
Armyworms follow a different lifecycle. Adult moths lay eggs, which hatch into caterpillars. Those caterpillars progress through several stages of growth while feeding before pupating and eventually emerging as adult moths.
This is why understanding lifecycle and timing can matter when managing recurring pest problems. What you see damaging the lawn may only represent one stage of the insect’s development.
When Are Lawn Grubs Most Active In Australia?
Lawn grub activity varies according to the pest, location, weather and time of year, so there isn’t one universal “lawn grub season” across Australia.
Australia covers a wide range of climates, and different insects can have different seasonal patterns. Warm conditions may support increased insect activity, while rainfall, soil conditions and local pest populations can also influence when problems become noticeable.
Rather than relying on a particular calendar date, monitor your lawn during periods of active growth and warm weather and investigate unexplained changes early.
How To Get Rid Of Lawn Grubs
The appropriate way to get rid of lawn grubs depends on which pest is present and whether you’re managing an active infestation or trying to prevent future damage. Identify the pest first, then use a treatment specifically suitable for that pest and your lawn, following the product label.
The first objective is to stop active damage.
If you have confirmed an infestation, choose a treatment registered and labelled for the pest you’re dealing with. Application method and timing can differ, so avoid assuming that one lawn insect treatment is suitable for every type of grub.
Treating Curl Grubs
For a suspected curl grub infestation, first confirm that larvae are present beneath the turf and that the symptoms are consistent with below-ground damage.
Treatment needs to reach the area where the target pest is active, and timing can matter depending on the lifecycle and size of the larvae. Follow the directions of an appropriately labelled lawn treatment rather than increasing application rates in an attempt to get a faster result.
Treating Armyworms
Armyworm treatment focuses on controlling the active caterpillars responsible for feeding damage.
Because significant feeding can occur rapidly, early identification is valuable. Inspect affected turf and surrounding areas, confirm the presence of caterpillars and use an appropriately registered treatment according to its label.
What Should You Do After Treatment?
Don’t immediately assume the problem is solved because a treatment has been applied.
Continue monitoring the lawn for new damage and pest activity. Once you’re confident the active infestation has been brought under control, shift your focus towards helping the surviving turf recover.
Seed & Turf Expert Tip: Treat the cause before trying to repair the symptoms. Reseeding, fertilising or replacing damaged turf while an active infestation remains can waste time and money if the new growth is exposed to the same problem.
How To Prevent Lawn Grubs
You can’t guarantee that lawn pests will never appear, but regular monitoring and good turf management can help you identify problems earlier and keep your lawn better positioned to tolerate and recover from stress.
A dense, actively growing lawn generally has more capacity to recover from minor damage than turf already under stress. That means appropriate mowing, irrigation, nutrition and soil management remain important even though they won’t make a lawn immune to insects.
Pay attention to changes rather than waiting for severe damage. New thinning, unexplained discolouration, chewed foliage or unusual insect and bird activity are all reasons to inspect the lawn more closely.
Where preventative pest treatments are appropriate, their effectiveness can depend on targeting the correct pest at the correct stage of its lifecycle. Follow the label of any lawn-care product you use and seek professional advice when you’re uncertain about identification or treatment.
Will Your Lawn Grow Back After Lawn Grub Damage?
Yes, many lawns can recover after lawn grub damage once the active infestation has been controlled. Recovery depends on the severity of the damage, the amount of healthy turf and root structure remaining, the turf variety, season and growing conditions.
Light damage may only require time and appropriate lawn care. If enough healthy grass remains, actively spreading varieties may gradually move back into thinner areas during favourable growing conditions.
Moderate damage can require more intervention. Dead material may need to be removed and bare areas repaired while the remaining lawn receives appropriate water and nutrition.
Severe damage is different. Where large areas have lost both healthy foliage and viable root structure, repairing the existing lawn may be slower or less practical than re-establishing the affected area.
We’ve created a dedicated resource explaining how to repair your lawn from grub damage if you’re at the recovery stage.
How To Repair Lawn Grub Damage
Start repairing lawn grub damage only after the active pest problem has been controlled. The objective is then to give surviving turf the conditions it needs to recover while determining whether severely damaged sections need to be re-established.
Assess the lawn first. If the grass is still alive and roots remain healthy enough to support growth, recovery may involve removing excess dead material, correcting irrigation, providing appropriate nutrition and allowing the lawn to fill back in during its active growing season.
For more severe damage, bare areas may require reseeding, turf replacement or another establishment method appropriate to the lawn and site.
For larger areas where substantial re-establishment is required, hydroseeding may be worth considering depending on the grass variety, property and project requirements.
The important distinction is that pest control and lawn repair are two separate stages. Stop the ongoing damage first; rebuild the lawn second.
Common Lawn Grub Mistakes To Avoid
A common mistake is assuming that every brown patch is caused by lawn grubs. Treating without identifying the cause can waste time and potentially distract from the real issue, such as water stress, disease or poor soil conditions.
Another mistake is treating every “grub” as the same pest. Curl grubs and armyworms differ in appearance, feeding behaviour and lifecycle, so identification should come before treatment.
Waiting until the lawn is extensively damaged can also make recovery more difficult. Regular observation gives you a better chance of spotting unusual changes while the problem is still localised.
Finally, don’t focus entirely on killing the pest and forget about the lawn itself. Once an infestation is controlled, damaged turf may still require appropriate watering, nutrition and time to recover.
Think You Have Lawn Grubs? Start Here
If you’re looking at lawn damage right now and aren’t sure what to do next, work through the problem in this order:
- Examine the symptoms. Look for discolouration, thinning, chewed foliage, root damage and unusual bird activity.
- Inspect the turf. Check the grass itself and, where appropriate, the soil beneath damaged areas.
- Identify the pest. Determine whether the evidence points towards curl grubs, armyworms or another problem.
- Rule out other causes. Consider irrigation, heat stress, disease, soil and nutrition before assuming insects are responsible.
- Control an active infestation. Use an appropriate treatment for the pest you’ve identified and follow its directions.
- Monitor the lawn. Check whether fresh damage and pest activity have stopped.
- Begin recovery. Once the problem is controlled, focus on restoring or re-establishing the affected turf.
That sequence matters. Identify, Treat, Monitor, then Recover.
Frequently Asked Questions About Lawn Grubs
What Do Lawn Grubs Look Like?
The appearance of lawn grubs depends on the pest. Curl grubs are generally pale or cream beetle larvae with darker heads and a characteristic C-shaped body. Armyworms are caterpillars with elongated bodies and may have visible stripes. Where the pest is found can also help with identification.
What Are The Signs Of Lawn Grubs?
Potential signs of lawn grubs include yellow or brown patches, thinning grass, damaged roots, chewed foliage, turf that lifts more easily and increased bird activity. No single symptom confirms an infestation, so inspect the lawn for visible pests or additional evidence before treating it.
How Do I Know If I Have Lawn Grubs?
Inspect damaged turf, particularly around the boundary between healthy and affected grass. Check beneath the turf for curl grubs if root damage is suspected, or inspect the foliage, thatch and grass surface for caterpillar activity if leaves appear eaten. Brown grass by itself does not confirm lawn grubs.
How Do I Get Rid Of Lawn Grubs?
First, identify the pest responsible for the damage. Once confirmed, choose a lawn treatment specifically labelled for that pest and suitable for the application, following the manufacturer’s directions. Different pests and lifecycle stages can require different approaches, so avoid treating all lawn grubs as interchangeable.
What Is The Difference Between Curl Grubs And Armyworms?
Curl grubs are beetle larvae that live beneath turf, while armyworms are the caterpillar stage of moths and primarily feed on grass foliage. Their appearance, feeding behaviour and damage patterns differ, which is why identifying the pest before choosing a treatment is important.
Can Lawn Grubs Kill Grass?
A severe infestation can cause substantial lawn damage and may kill affected turf, particularly where roots or large amounts of foliage are lost. The outcome depends on the pest, severity of the infestation, health of the lawn and how quickly active damage is brought under control.
Will Grass Grow Back After Lawn Grub Damage?
Many lawns can recover after lawn grub damage if the infestation is controlled and enough healthy turf remains. Minor damage may repair naturally during active growth, while moderate or severe damage may require additional lawn care, patch repair or re-establishment.
Do Birds On My Lawn Mean I Have Lawn Grubs?
Not necessarily. Increased bird feeding can indicate insects or larvae are present, but birds feed on many organisms found in lawns. Treat bird activity as a reason to inspect the turf rather than confirmation of an infestation.
Why Do Lawn Grubs Keep Coming Back?
Recurring lawn grub problems can be influenced by the pest’s lifecycle, seasonal conditions, and local insect populations. If infestations repeatedly occur, identifying the specific pest and understanding when its damaging stage is active can help inform a more targeted management strategy.
When Should Lawn Grubs Be Treated?
Treatment timing depends on the pest, lifecycle and whether you’re controlling an active infestation or taking preventative action. Once active damage is identified, address the problem promptly using an appropriately labelled treatment. Preventative approaches may rely on different timing, so follow product guidance for the specific pest.
Keep Your Lawn Healthy Beyond The Infestation
Finding lawn grubs doesn’t necessarily mean starting your lawn again. The key is to identify what you’re dealing with, confirm whether active damage is occurring, treat the problem appropriately and then give the lawn the conditions it needs to recover.
Remember the process:
Identify the symptoms → Confirm the pest → Rule out other causes → Treat active damage → Monitor the lawn → Repair affected turf → Focus on prevention.
If your lawn has suffered significant damage, Australian Seed & Turf Farm can help you understand your options for restoring or re-establishing the area. With more than 100 years of collective turf industry experience, our team can provide advice based on your lawn, site and requirements.
Explore more expert advice through the Seed & Turf blog, or visit Australian Seed & Turf Farm to learn more about our turf, lawn establishment services and expert support.
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