Common Insects and Weeds

Common Lawn Insects, Weeds & Diseases in Sydney

A healthy lawn is always under pressure from pests, weeds, and diseases — especially in Sydney’s changing climate. Knowing what to look out for (and how to respond) will help you keep your turf lush and green all year round.

---

🐞 Common Lawn Insects & Pests

Black Beetle
A common summer–autumn pest that feeds on lawn roots.

• Symptoms: Grass dies in patches for no obvious reason; roots are damaged, leaving the lawn brown and discoloured.

Army Worm
Caterpillars that feed in large groups, often striking overnight.

• Appearance: Brown, greenish-brown, or black with striped/triangular markings.
• Symptoms: Leaves eaten down to the roots; moth activity over lawns signals egg-laying.
• Season: Most common from summer through early autumn.

Lawn Grub (White Curl Grubs)
Larvae of scarabs, cockchafers, and Christmas beetles.

• Symptoms: Grass wilts and dies as roots are eaten. Lawn lifts easily like carpet when infestation is heavy.

Billbug (Weevil Larvae)
Small white grubs that attack grass crowns and roots.

• Symptoms: Thinning patches and weak, brown turf, especially in warm months.

---

🌱 Common Lawn Weeds

Nutgrass
Perennial weed with wiry roots and small underground nuts.

• Appearance: Tall, stringy grass-like leaves.
• Conditions: Thrives in waterlogged or poorly drained soils.

Clover
A widespread lawn weed, particularly in damp conditions.

• Risk: Kikuyu and Couch lawns are especially prone.
• Season: Common in winter and early spring.

Bindii (Jo-Jo)
A low-growing winter weed that produces sharp seed heads.

• Symptoms: Painful burrs in summer, making lawns uncomfortable for children and pets.

Winter Grass (Poa annua)
Soft, light-green clumps that invade lawns in cooler months.

• Symptoms: Masses of white seed heads that spread easily.

Crowsfoot Grass
An upright annual weed that quickly produces seed heads.

• Conditions: Thrives in compacted, nutrient-poor soils.

Oxalis (Soursob)
Low-growing with clover-like leaves and yellow or purple flowers.

• Symptoms: Rapid spread through bulbs, making it difficult to control.

---

🍂 Common Lawn Diseases

Dollar Spot
A fungal disease leaving small, straw-coloured circles (about the size of a dollar coin).

• Conditions: Warm, humid weather and underfed lawns.

Brown Patch (Rhizoctonia)
A serious fungal disease that creates large, spreading brown patches.

• Conditions: Warm, humid weather with excess moisture.

Rust Fungus
Appears as yellow-orange powdery spores on blades.

• Conditions: Shady, damp lawns with poor airflow.

Powdery Mildew
White, powdery coating on leaves.

• Conditions: Shaded, humid areas with poor circulation.
• Impact: Weakens lawn and encourages thinning.

---

🌿 Protecting Your Sydney Lawn

• Regular maintenance — mow, water, and fertilise correctly to keep turf healthy and resilient.
• Early action — treat pests, weeds, and fungi before they spread.
• Good drainage — prevents waterlogging that encourages weeds and fungal outbreaks.
• Balanced feeding — keeps grass strong enough to outcompete weeds.