List of Common Lawn Pests

Common pests in Queensland lawns can surprise any homeowner. In the Sunshine Coast and Gympie region, our subtropical climate means a range of grass insects and turf pests can be nibbling your turf nearly year-round, causing serious lawn damage. Common lawn pests – from white curl grubs to cutworms – can cause unsightly brown patches or even make your grass peel up like a carpet. By learning to identify each type of pest and its damage, you can tackle infestations early and keep your lawn healthy. We at Robert’s Turf Supplies have seen these issues firsthand, so we’re outlining what to look for and how to treat them.

African Black Beetle (White Curl Grubs)

African black beetles (Heteronychus arator) are shiny black turf pests about 12–15 mm long. Adult beetles emerge in spring and lay eggs in the soil, where the creamy C-shaped larvae (white curl grubs) hatch and feed on grass roots. This root feeding often shows up as patches of lawn that yellow and then turn brown. One telltale sign of heavy grub damage is turf that starts to slip or roll up like a carpet – if you see this, dig into the soil and you’ll find the plump white grubs. Birds pecking at the turf for insects can be another clue.

In our subtropical climate, African black beetles generally have one generation per year. Most injury from these pests happens in late spring and summer as the larvae grow. Targeting the beetles early is key to getting rid of these pests – small first and second instar grubs are much easier to kill than larger third instars. For this reason, preventive treatment in spring is recommended. For example, Acelepryn pesticide (chlorantraniliprole) applied in mid-spring (around September) provides season-long control. A single application of Acelepryn can protect your lawn for up to 6 months, killing the grubs as they hatch and preventing lawn damage.

If infestations are small, natural methods can help reduce pest pressure. Pouring a bucket of soapy water on the turf at night will draw grubs to the surface, where birds or you can pick them off. Beneficial entomopathogenic nematodes (tiny roundworms) can also be applied as a soil drench to infect and kill grubs. However, the most reliable approach is early detection and targeted treatment. If you suspect your lawn has a grub problem, you can contact us for help – see our 8-week lawn care programme that can save your turf.

Argentine Scarab

Argentine Scarab (Cyclocephala signaticollis) is another white curl grub turf pest, originally from South America. The adult Argentine scarab beetle is very similar in size and shape to the African Black Beetle, but it has a lighter tan colour with faint striping on its wing covers. After being first detected in Australia in the 1950s, Argentine scarab has spread through eastern states and can now cause turf damage here as well. In particular, its larvae start to feed on grass roots from about December onwards, and can reach very high densities (some trials have seen up to 350 larvae per square metre feeding on roots). Like African black beetle grubs, scarab larvae weaken the grass and result in brown, dying patches and turf that can pull up easily. You may also notice birds feeding on the turf in summer.

Management is similar to other scarab grubs. Early detection is key – treat preventively if possible. If you see unexplained summer browning in your lawn, dig down to check for these tan grubs and act quickly.

Billbugs (Weevils)

Billbugs (often called La Plata weevils) are snouted beetles about 10–13 mm long. The adults are dark brown and have a long curved snout, but it’s the creamy, legless larvae that do the damage. Billbug larvae hatch from eggs laid in spring and feed inside grass stems and crowns. The result is dead clumps of turf: aboveground stems break off at the base, and the clumps pull out easily with hollow, sawdust-filled stalks. Initially the grass turns yellow and then brown as the plants die.

Billbugs prefer warm-season grasses like kikuyu and couch. In our region, adults emerge in late winter/spring, and by late spring the stem-feeding larvae can cause noticeable damage. Prevention and early action are key: monitor for irregular brown patches and check pulled-up clumps for larvae. Acelepryn pesticide is labelled to control billbug larvae and other weevil pests, giving season-long protection with one spring application. For small problems, digging up and removing affected clumps can reduce the larval population.

Lawn Armyworm

Lawn armyworms (Spodoptera spp.) are caterpillars that feed heavily on turf leaves and can quickly strip sections of grass in warm months. The larvae are smooth-bodied and grow up to 3–4 cm long; they have greenish or brownish bodies with pale white and yellow stripes and a distinctive white “Y”-shaped mark on the head. Young armyworms often feed together in groups, especially in the evening, so an infestation can suddenly chew large patches of turf overnight, leaving ragged blade edges or bare ground. If you pull apart affected turf, you may even find dozens of wriggling caterpillars.

Armyworms can have two to three generations per year in Queensland, especially after heavy rain. Prevention and early action help stop big damage. Maintain a healthy, well-fertilised lawn so it can recover quickly from any feeding. For severe outbreaks, insecticide control is usually needed.

Sod Webworm

Sod webworms (Herpetogramma licarsisalis) are small, greenish-brown caterpillars (2–3 cm long) that feed on grass blades at night. The larvae hide in the turf during the day, often lining their hiding spot with silk. Adult moths are grey with black spots, but it’s the caterpillars that cause the damage. Sod webworm larvae cut off grass leaves near the base; early instars often clip small blades and drag clippings into their tunnels. They leave behind ragged edges on the grass blades. Initial damage appears as small brown patches in the lawn that may be mistaken for disease or drought. If you inspect a patch closely, you may see grass with frayed blade edges or loose grass at the edges of dead spots.

In Queensland, sod webworms hatch from eggs laid in spring and can produce multiple generations through summer. To identify them, shake a towel or cloth over the grass at dusk – the caterpillars will fall onto it when disturbed. For control, keep the turf growing strongly so it can recover quickly. Acelepryn pesticide is registered for sod webworm and provides long-lasting control – a spring application will protect new grass for months by killing larvae as they feed. For severe infestations, a spray or bait applied in the evening (when caterpillars are active) can quickly reduce numbers. Always water lightly after treatment and fertilise the lawn to aid recovery.

Cutworm

Cutworms are the caterpillar larvae of several moth species (common, pink and black cutworms). These pests stay in the soil during the day and emerge at night to feed. They often sever grass seedlings or blades at the soil surface. A classic sign of cutworm damage is a small, round bare patch (about the size of a golf ball) with a little entrance hole in the middle – the caterpillar’s tunnel. Many small holes can merge and kill a larger area of turf. The edges of such patches usually show grass blades cut off near ground level. Cutworms are most active on warm summer nights.

Preventive steps include keeping the lawn mowed to reduce hiding spots and maintaining healthy turf that can outgrow light feeding. For heavy cutworm infestations, insecticides are usually required. For immediate knockdown, sprays with bifenthrin or another pyrethroid applied at night will kill larvae quickly. After treating, irrigate the lawn well to help it recover.

Argentine Stem Weevil

Argentine Stem Weevil (Listronotus bonariensis) is a small grey weevil whose larvae attack grass crowns. The larvae are tiny (about 4–5 mm), creamy grubs that bore into the base of the grass plant and feed on the growing point. Infested grass often turns a dull yellow then brown, especially in winter/spring. You may notice small dead patches or scattered clumps of affected grass. The damage can be mistaken for drought stress, but pulling up a brown clump often reveals the little stem weevil larvae at the base. Adult weevils are about 6 mm long, greyish, and can sometimes be found around the plant crowns.

Control timing is important. Since the larvae feed in cooler months, early spring treatments are recommended. Avoid excessive fertiliser in late summer, as lush new growth can attract more egg-laying weevils. For persistent problems, our turf services can arrange targeted insecticide treatments to eliminate these pests.

Mole Cricket

Mole crickets are large, burrowing insects that can wreak havoc on a lawn by chewing on roots and creating a maze of tunnels underground. They have spade-like front legs for digging and spend most of their time underground. Lawn damage from mole crickets may not show as a simple brown patch – instead you’ll see weird ridges, holes or sunken trails on the turf surface, and the grass may wilt as its roots are eaten. Because mole crickets are active at night, you often only find them by setting traps or pouring soapy water on the grass at night, which forces them to the surface.

Controlling mole crickets can be tricky. Treatments should be applied when the crickets are active – usually warm summer evenings (above 16°C). Insecticides containing ingredients like abamectin, bifenthrin or imidacloprid can work if watered in to reach their burrows. (Acelepryn pesticide is also effective against mole crickets if they come up to feed on treated turf.) After treatment, irrigate the lawn well to drive the chemical into the soil and help the grass recover. Aerating the lawn also helps eliminate thatch and encourages grass regrowth. In wet seasons, it’s best to keep an eye out for mole cricket holes so you can retreat if needed.

Ants (Including Fire Ants)

Most common lawn ants (like Argentine ants or black ants) don’t eat grass but can still cause tiny raised mounds in turf. These little volcano-like mounds make the lawn uneven, and some species (like Argentine ants) can farm aphids that harm plants. In general, small ant colonies aren’t a huge turf pest, but they can be a nuisance or lead to other minor problems.

A more serious concern in Queensland is the Red Imported Fire Ant (Solenopsis invicta). Fire ants build large mound nests (up to 40 cm high) that scar the turf surface. They are highly aggressive: thousands of stinging ants in a mound can inflict many painful bites. A fire ant attack can injure or kill young animals and poses a serious safety hazard. Fire ants are a regulated pest (Category 1) under QLD biosecurity law, so if you find a suspected fire ant nest, report it to the authorities immediately. Never move soil from an infested area, and use only approved fire ant baits or treatments. Always wear protective clothing when treating or removing fire ant mounds to avoid stings.

Other Minor Turf Insects (Leafhoppers, Aphids, Caterpillars)

In addition to the major pests above, you may occasionally see other insects in your lawn. Leafhoppers or grasshoppers may nibble on grass but rarely cause lasting damage – they usually cause tiny spots of discoloration at most. Aphids seldom live on turf; they usually feed on plants at the lawn edge, sometimes causing sticky honeydew. Small caterpillars (other than armyworms or webworms) might eat a few grass blades, but serious infestations of minor caterpillars are uncommon in a healthy lawn. In most cases, these minor insects do minimal harm, and a vigorous lawn will tolerate them. Good lawn care will keep these minor pests in check, and if you spot them, they can often be hand-picked or sprayed locally.

Why Lawn Pests Are a Problem

Lawn pests may be small individually, but together they can do big damage. Grubs, weevils and caterpillars destroy roots and blades, robbing the grass of water and nutrients. For example, heavy white curl grub infestations cause a lawn to yellow out and then brown off as the grass dies, often looking like drought stress. Infested turf starts to slump and even peels up like a carpet. Any pest activity that kills grass opens the door for weeds, diseases and weeds, so one pest problem can easily lead to many others. In short, pests weaken your lawn’s resilience – a small infestation now can become a major turf problem if not dealt with.

How to Identify Lawn Pest Damage

White Curl Grubs (e.g. African Black Beetle, Argentine Scarab) – Look for irregular brown patches that pull up easily. The turf often peels up like a carpet, revealing the C-shaped grubs beneath.
Billbugs and Weevil Larvae – Infested spots have dead clumps of turf. The grass stems break off at the crown and the clumps pull out easily, with hollow, sawdust-filled stalks.
Armyworms – Large areas of grass are eaten down, usually overnight. Check for chewed or shredded grass blades and even dozens of caterpillars in the cut turf.
Sod Webworms – Damage appears as small brown patches with ragged edges on the grass blades. Inspecting the thatch at dusk may reveal loose silken tunnels with hidden caterpillars inside.
Cutworms – Look for small circular dead patches (about 5 cm across) often with a central hole in the thatch. The edges of the patch will show blades cut off near ground level.
Stem Weevils (Argentine Stem Weevil) – In cool-season lawns, you may see tiny yellow or brown patches in winter. Affected grass often wilts and browns from the tip downward. Pulling up the dead turf may reveal tiny weevil larvae at the base.
Ants (Fire Ants) – Large raised mounds are a giveaway of ants, especially fire ants. The mounds make the lawn uneven and should be treated promptly to avoid stings and further damage.

Using these clues will help pinpoint which pest is causing the lawn damage, so you can treat it correctly. If you’re unsure, dig into the soil to look for insects or call a professional for an identification.

When Lawn Pests Are Most Active

In our subtropical climate, most turf pests have a clear seasonal cycle. As spring arrives (around September), scarab beetles and weevils start to lay eggs, and their larvae feed through summer. Research shows that white curl grub damage in Queensland lawns is most common from November through January. Moth pests like sod webworm and armyworm typically hatch in early summer, with multiple generations feeding into autumn. Cutworms cause the worst damage on warm summer nights.

In contrast, some pests like Argentine stem weevil larvae feed in cooler weather. Understanding this timing is key to control. For instance, Acelepryn’s instructions highlight an early spring application (mid September) when overwintered adults first appear. This targets pests before their larvae cause visible damage. Keep an eye on the weather and your lawn: after warm rains, caterpillars and larvae can multiply quickly. Monitoring your turf through the seasons will help you apply treatments when they’ll be most effective.

Integrated Lawn Pest Management Tips

Lawn Health: Keep your turf thick and vigorous by mowing at the correct height, watering properly, and fertilising as needed. Healthy grass can often outgrow small pest outbreaks. Dethatch and aerate if thatch becomes heavy, as a clean turf canopy is less inviting to pests.
Monitoring: Inspect your lawn regularly. You can trap and spot pests by placing a moist piece of hessian or wood on the grass overnight to collect beetles. You can also pour a bucket of soapy water on suspected patches – grubs and caterpillars will surface, making them easy to collect. Early detection is the first step to control.
Beneficial Nematodes: These microscopic worms can be applied to the soil to infect and kill many turf pests without harming other wildlife or the grass. Use nematodes on affected areas (when soil is warm and moist) to reduce grub and caterpillar numbers. They’re a great organic option.
Targeted Insecticides: If pests are confirmed and damage is severe, use a product designed for lawn insects. For example, Acelepryn pesticide provides season-long control of white grubs, weevil larvae and caterpillars with one spring application. It’s low-toxicity and long-lasting. Always follow the application instructions and only treat the areas that need it. Avoid blanket spraying – spot-treat where pests are active.
Professional Help: Sometimes it’s best to call in the pros. Check our services page for expert advice, soil testing, and customised pest control programs. We can help diagnose the problem and apply treatments safely and effectively, so you get your lawn back on track.

Frequently Asked Questions

Q: When should I treat my lawn for pests like grubs?
A: The best time is before damage appears.This ensures control of larvae before they feed heavily on roots. Treatments later in summer can still kill pests, but once brown patches form it’s harder to protect the turf.

Q: Is Acelepryn safe for bees and pets?
A: Yes, Acelepryn is considered low-risk for non-targets. It has a greatly reduced impact on beneficial insects like bees and earthworms.

Q: How do I deal with fire ants in my lawn?
A: Fire ants are a regulated pest in Queensland. If you find a fire ant mound, it’s best to contact local authorities or a pest professional. Never move soil or turf from the area, and wear protective clothing. Use only approved fire ant baits or treatments labelled for control of fire ants. Safety first: always avoid being stung during any treatment.

Q: What if I only have a few grubs?
A: If grub numbers are low (under ~25 per square metre), a healthy lawn may outgrow minor damage. In that case, maintain good lawn care and monitor the situation. You can also try organic approaches like nematodes or simply remove grubs by hand. Treat chemically only if damage is significant or grubs are abundant.

Q: Do I have to treat the whole lawn?
A: You can spot-treat small problem areas, but remember that pests often spread. If you see multiple patches or large areas affected, treating the entire lawn ensures complete control. Always follow product directions for coverage rates and apply only as needed to minimize cost and chemical use.

Keep Your Lawn Healthy and Pest-Free

Preventing pests is always easier than fixing the damage after. Keep your lawn well-maintained – mow at the recommended height, water properly, and fertilise on schedule. Inspect your turf after rain or during peak pest season, and treat early if you spot trouble. By staying on top of weeds, thatch and drainage, your lawn will be less attractive to pests and quicker to recover.

And remember, we’re here to help. Our team at Robert’s Turf Supplies has years of local experience with Sunshine Coast and Gympie lawns. If you ever need advice or assistance, just give us a call. We’re always happy to share our knowledge and help keep your grass looking great.