How to get rid of ants in the house (and keep them out)

To get rid of ants in the house, deal with the nest, not just the trail. Wipe up the trail and anything sweet or greasy it leads to, follow the ants back to where they’re getting in, and treat the nest or the entry points. Baits work for some species if you leave them alone long enough. If the trails keep coming back, a professional treatment of the trails, entry points and colony usually settles it in one visit.

Spring is when the calls start. Warmer weather wakes the colonies up, and over the next few months we see trails along skirting boards, across kitchen benches, around pet bowls and up the bathroom wall in homes from Gawler to the Barossa. Here’s what’s going on, and what you can do about it.

Why ants come into the house

Ants are social insects that live in permanent nests and send workers out to find food. According to Victoria’s Department of Health pest control technical note on ants, they leave chemical trails called pheromones to lead other workers to a food source. One ant finds a crumb, and before long there’s a line of them.

The same note says that of more than 4,000 known ant species in Australia, only a handful are considered pests, and most of those are introduced species. Pest ants often nest in and around buildings and gather in food preparation areas. Food left outside, such as pet food, can draw them close to the house too.

Ant activity spikes in spring and early summer, and again when hot, dry spells push colonies indoors looking for water. That’s why trails often appear in the kitchen, laundry and bathroom.

Which ants are in your house?

Knowing the ant helps, because different species respond to different treatments. These are some of the common house-infesting ants described in the Victorian technical note:

• Black house ants: small, intensely black ants that like sweet foods. They nest outside around paths and rockeries, and also inside ceilings, cavity walls and subfloors. The WA Department of Primary Industries fact sheet adds that they can turn up in pot plants and even electrical items like kettles and microwaves.
• White-footed house ants: shiny black ants with light-coloured feet (you need a magnifier to see them), more active at night. They usually nest outdoors, but will set up small nests in wall cavities and behind cupboards and skirtings near a reliable food supply.
• Coastal brown ants: shiny, light to dark brown ants. The soldiers have large heads. They nest outside around paths and rockeries, often show up in wall crevices and behind skirtings, and prefer meat, grease and dead insects to sweets.
• Argentine ants: slender brown ants that travel in slow, well-defined trails up to three or more ants wide. They prefer sweet foods, nest in lawns, around the edges of buildings and paths and at the base of trees, and may move indoors in wet weather.

If you’re not sure what you’ve got, take a clear photo of a few ants on a white surface. It makes it much easier to tell species apart.

What you can do yourself

Start with the basics. They won’t fix an established colony on their own, but they make every other step work better:

• Wipe the trail away with warm soapy water, so there’s less scent for the rest of the colony to follow.
• Clean up crumbs, spills and grease, and keep sweet things like honey, sugar and soft drink sealed.
• Don’t leave pet food sitting out, and rinse pet bowls after meals.
• Fix dripping taps and leaks under sinks, since ants come looking for water in hot weather.
• Trim back plants and branches touching the walls or roof, which give ants a bridge into the house.

Then follow the trail. Watch where the ants are coming from: a gap under the skirting, a crack in the window frame, a hole beside a pipe. That’s where the colony gets in, and it’s the place to focus on.

Baits, sprays and why the trail keeps coming back

The Victorian technical note explains that direct treatment of the nest usually gives the most effective control. Surface sprays on nesting sites, travel routes and entry points, combined with good hygiene, should give long-term prevention. Baits are useful when you can’t find the nest: workers carry the bait home and share it with the rest of the colony. Baiting is slow, though, and needs patience.

The WA fact sheet makes two points worth remembering. Control is easier when numbers are low, and once ants start feeding on a bait, don’t disturb it. Spraying the ants on top of a bait station kills the very workers that were about to carry it home.

That’s also why a can of surface spray on the bench rarely ends the problem. It kills the ants you can see, and the nest just re-routes the trail. Some species even react badly to the wrong treatment. The note warns that spraying Pharaoh’s ants fragments the colony into new nests and makes the infestation worse. Whatever product you use, read the label, follow its directions, and keep baits and sprays well away from children and pets.

When to call a professional

It’s time to get help if the trails come back every few days, if you’re seeing ants in several rooms, if they’re nesting inside walls or electrical items, or if you’ve tried baits for a couple of weeks without a change. The Victorian note says follow-up treatments may be needed for severe infestations, and that an Argentine ant colony can cover several hectares.

Our ant control treats the problem at the source: the active trails and entry points inside and out, plus a colony-control strategy aimed at the nest rather than just the ants you can see. For most homes it’s a single-visit job. If your species needs a follow-up, we’ll tell you that upfront. We apply professional products to label directions and explain anything you need to know about kids and pets before we start.

If you’d rather stay ahead of it, ants are also covered in a general pest treatment, which suits homes that see trails every spring.

Ant control around Gawler and the Barossa

We treat homes all around the Barossa, mainly Nuriootpa and Tanunda, plus Gawler, Evanston and Willaston. If ants have moved in for the season, call Garry on 0403 018 325 for a free quote. If cockroaches are the other kitchen visitor, our guide to German cockroaches covers those too.