Ant Treatment in Melbourne

Common ant species in Melbourne

Australia has thousands of ant species, but only a handful, mostly introduced, become pests in homes and businesses. Each one nests and feeds differently, which changes where we look and how we treat.

• 

  Argentine Ants

  Multi-queen colonies that can spread across neighbouring properties.

  Look for

  Slender and brown, about 1.5–3 mm long, with no smell when crushed. They travel in well-defined trails, often several ants wide, and climb walls, trees and shrubs.

  Found in

  Mostly outdoors, in soil, under paving and in garden beds, often trailing up trees and shrubs to feed on honeydew from aphids and scale insects. They tend to move indoors in wet weather.

  Treatment focus

  Each nest has many queens and one colony can stretch across several properties, so treating a single nest rarely solves the problem. Treatment covers the whole property, from the building's perimeter and foundations to path edges and the base of trees and shrubs, and ants from next door can move back within a couple of weeks, so a second treatment is often needed.

• 

  Black House Ants

  Trail indoors and often nest in walls and ceilings.

  Look for

  Small, about 2.5–3 mm long and intensely black, sometimes with a purplish-green sheen. Crushed, they give off a strong, distinctive smell, though not everyone can pick it up.

  Found in

  Outdoors along paths, rockeries and garden edges, and indoors in ceilings, wall cavities and subfloors. They're drawn to sweet food and to aphids on indoor pot plants.

  Treatment focus

  Because they nest inside the building as well as outside, treatment follows the trails back to wall and ceiling voids and the gaps they come through, not just the bench where they're feeding.

• 

  Coastal Brown Ants

  Push soil up between pavers and along concrete edges.

  Look for

  Shiny, light to dark brown and about 1.5–3 mm long. Larger soldiers, 3.5–4.5 mm long, have oversized heads and strong jaws.

  Found in

  Soil under paths, paving and rockeries, where they leave small mounds of loose soil. Indoors they nest in wall cavities and behind skirting boards, and they prefer meat, grease and dead insects to sweets.

  Treatment focus

  Colonies have many queens across connected nests, so treatment targets the nests under paving and along the building as well as any activity in the walls. Baits need to suit their taste for protein and fat.

• 

  White-footed House Ants

  Large colonies in walls, roofs and gardens.

  Look for

  Shiny black, about 2.8–3.5 mm long, with pale feet you may only see up close. In Victoria they're often just called black ants.

  Found in

  Usually outdoors in gardens and moist, shaded areas, but also indoors in wall cavities, roof voids and behind cupboards and skirting boards. They're most active at night and come in through small cracks.

  Treatment focus

  They don't pass food through the colony the way most ants do, so baits work slowly and need patience. Colonies can split into new nests, so treatment often pairs baits indoors with treating outdoor nests and foundations.

• 

  Carpenter Ants

  Often nest in damp or decaying timber.

  Look for

  From about 2.5 mm up to 14 mm long, making them the largest of these species, and brown to pale brown. Sometimes called sugar ants. They can bite but don't sting.

  Found in

  Decaying wood, soil, between rocks and in tree roots and twigs. They mostly forage at night, travel long distances and rarely come inside.

  Treatment focus

  They prefer damp, rotting timber to sound wood, so they rarely cause structural damage. Treatment targets the nest, and we'll point out any damp timber that's drawing them in.

• 

  Other Ant Species

  Identified before we treat.

  Look for

  Ants that don't match the species above. Pharaoh ants, for example, are tiny and yellow-brown to darker brown, about 1.5–3 mm long.

  Found in

  Pharaoh ants nest in warm, hidden spots such as near heating ducts, and are more often a problem in hospitals and aged care than in homes.

  Treatment focus

  Spraying Pharaoh ants splits the colony into new nests and makes the problem worse. It's one reason we identify the ants before choosing a treatment.