Argentine ants form super-colonies across Melbourne suburbs. Learn how to identify them, why store sprays fail, and what actually stops the trails for good.
What Are Argentine Ants?
Argentine ants (Linepithema humile) are one of Melbourne's most persistent household pests. They are small (2–3 mm), dark brown, and travel in dense trails along skirting boards, kitchen benches, and garden edges. Unlike many native ants, they form multi-queen "super-colonies" that can stretch across neighbouring properties — which is why killing the ants you see rarely solves the problem.
How to Tell Argentine Ants from Other Ants
- Size: tiny and uniform — no large soldier caste
- Trails: very busy, continuous lines of ants, often indoors and outdoors
- Nesting: under pavers, in wall voids, mulch, pot plants, and around moisture
- Behaviour: swarm food sources quickly, especially sweet and protein scraps
If you have trails returning within days of spraying, you are likely dealing with Argentine ants or another multi-nest species. See our full ant control service and guide on how to get rid of ants in Melbourne.
Why DIY Sprays Make Argentine Ants Worse
Repellent sprays kill the ants on the trail but scatter the colony. Surviving queens simply move deeper into walls or next door, then send new foragers back. You get a short quiet period, then a bigger rebound. Gel baits work better because workers carry poison back to the nest — but the wrong bait matrix, or spraying over bait placements, will stop them feeding.
What Professional Argentine Ant Treatment Involves
Effective control combines non-repellent residuals around entry points with strategically placed gel baits matched to what the colony is currently feeding on. Technicians also treat outdoor harbourages — pavers, garden beds, meter boxes, and weep holes — because indoor trails usually start outside. Multi-unit blocks often need coordinated treatment so ants cannot retreat into untreated units.
Prevention That Actually Helps
- Wipe benches nightly and store pet food in sealed containers
- Fix leaking taps and reduce moisture under sinks
- Keep mulch and garden waste pulled back from the slab edge
- Seal gaps around pipes, windows, and weatherboards
For stubborn trails across your kitchen or courtyard, book professional ant control or call 0416 528 547.
