Argentine Ant

Where it lives

Nests under paving slabs, in wall cavities, planters, irrigation lines and beneath rubble walls. Colonies move indoors during the summer drought and again after heavy autumn rain, following water pipes and skirting boards.

Signs

• Continuous trails of small brown ants along walls, worktops and window frames
• Ants appearing around pet bowls, bins and sweet spills within minutes
• Fine soil deposits pushed up between paving slabs or floor tiles
• Swarms of ants on outdoor citrus and hibiscus, farming aphids for honeydew

Risks

• Contaminates food preparation surfaces and open food
• Can carry bacteria picked up from drains and refuse areas
• Protects plant pests such as aphids and scale, damaging gardens
• Occasionally short-circuits electrical fittings when nesting inside them

Prevention

• Wipe up sugar, honey and fruit juice immediately. A single spill re-recruits the whole trail
• Store sugar, cereals and pet food in sealed containers
• Seal gaps around water and waste pipes with silicone or steel wool
• Keep planters and irrigation lines a hand-width away from external walls
• Do not spray the trail: it splits the colony and creates several new ones

Treatment

Argentine ants are controlled with slow-acting sugar-based gel and liquid baits placed on the trail so foragers carry the active ingredient back to every queen. We map the trails, bait the routes, treat the external nesting harbourage with a residual barrier and return after 10–14 days to confirm the colony has collapsed.