How to get rid of ants

Why spraying the trail fails

The ants you can see are foragers, and a colony can have thousands of workers plus one or more queens somewhere else entirely. Killing the visible ones changes nothing about the colony's size, so replacements walk the same trail a few days later.

Worse, spraying can make bait less effective afterwards, because ants avoid the treated surface - so the DIY attempt actively gets in the way of the thing that would have worked.

Leave the trail alone while bait works

This feels wrong and it's the key to it. The trail is the delivery route: foragers take bait back and share it through the colony, including with the queen. Wiping the trail away mid-treatment breaks the supply line.

Expect ant numbers to look worse for a day or two before they drop off. That's the bait being found.

Argentine ants are a different proposition

Argentine ants are established across parts of Auckland and behave unlike ordinary household ants: separate nests don't fight each other, so colonies join up into supercolonies spanning whole streets.

That's why a heavy, persistent trail can come back within weeks no matter what you do to your own property - you're treating a fraction of something much larger. If your trails are unusually dense and keep returning, it's worth having the species confirmed.

Remove what brought them in

• Pet bowls left down overnight
• Crumbs and spills under and behind appliances
• Sweet items stored in unsealed packaging
• Moisture around sinks, dishwashers and leaking pipework
• Planting or mulch touching the outside of the building