Nothing is more frustrating than watching your carefully maintained Canberra lawn develop mysterious brown patches that spread despite regular watering. The culprit is often lurking just below the surface — lawn grubs, the larvae of various moth and beetle species that feed on grass roots and stems, causing extensive damage in a surprisingly short time.
Understanding Lawn Grubs in Canberra
Several species of lawn grubs affect Canberra lawns, each with different life cycles and feeding patterns. The most common include army worms (Spodoptera spp.), sod webworms (Herpetogramma licarsisalis), and curl grubs (the larvae of African black beetles and other scarab beetles).
Army worms and sod webworms are caterpillar-like larvae that feed on grass blades at night, cutting them at the base. Curl grubs are C-shaped, cream-coloured larvae that feed on grass roots underground, causing turf to die from below.
When Is Lawn Grub Season?
| Grub Type | Peak Season | Feeding Habit |
|---|---|---|
| Army Worms | Feb – April | Eat grass blades at night |
| Sod Webworms | Jan – March | Cut grass stems at soil level |
| Curl Grubs | March – May | Feed on roots underground |
| Black Beetle Larvae | Feb – June | Destroy root systems |
How to Identify Lawn Grub Damage
Lawn grub damage in Canberra typically appears as irregular brown patches that expand over days or weeks. The key indicators include:
- The tug test: Damaged grass pulls up easily, like lifting a piece of carpet, because the roots have been eaten away
- Bird activity: Magpies, starlings, and other birds aggressively pecking at your lawn indicates grubs beneath the surface
- Night feeding signs: Green droppings (frass) visible on the lawn surface in early morning
- Moth activity: Small brown or white moths flying up from the lawn when you walk across it at dusk indicate adult stages laying eggs
- To confirm, dig into the edge of a brown patch. Curl grubs are white, C-shaped larvae 15-25mm long found 2-5cm below the surface. Army worms and sod webworms are caterpillar-like, 20-40mm long, and hide in the thatch layer during the day.
Treatment Options
Professional Lawn Grub Treatment
Professional treatments use commercial-grade products that provide faster action and longer residual protection than retail products. A professional application typically involves a targeted liquid spray using bifenthrin or chlorantraniliprole, applied in the late afternoon when grubs become active. These treatments deliver results within 24-48 hours and provide 6-8 weeks of ongoing protection.
Prevention Strategies
Healthy, well-maintained lawns are more resistant to grub damage. Regular fertilising promotes strong root growth that can tolerate some grub feeding. Correct mowing height (keeping grass slightly longer during grub season) helps turf survive attacks. Adequate watering ensures grass can recover from minor damage before it becomes visible.
Preventive treatments applied in late January or early February — before peak grub activity — provide the most cost-effective protection. A single preventive application often eliminates the need for emergency treatments later in the season.
Restoring Damaged Lawns
After successful grub treatment, lightly damaged areas typically recover on their own within 4-6 weeks with proper watering and fertilising. Severely damaged areas where the root system has been destroyed may require re-turfing or re-seeding. Late spring and early summer are the best times for lawn renovation in Canberra, when warm temperatures and longer days promote rapid grass establishment.
Brown Patches on Your Lawn?
Don’t let lawn grubs destroy your turf. Bugs Patrol provides fast, effective lawn grub treatment across Canberra with results in 24-48 hours.
Still have questions?
The best pest control company will solve your issue for a long time. Bugs Patrol is Canberra’s trusted choice for professional lawn grub treatment in Canberra with lasting results.
Frequently Asked Questions
Lawn grubs are most active from late summer through autumn (February-May). Army worms peak in February-March, while curl grubs feed from March-May.
Signs include brown patches that spread despite watering, grass that pulls up easily like carpet, increased bird activity on your lawn, and visible grubs when you dig into damaged areas.
Yes. Severe lawn grub infestations can completely kill sections of lawn by eating through grass roots. If untreated, the damage becomes permanent and requires re-turfing.
