Ants
Does ant bait work, and which kind should you use?
Which ant bait suits which ant: gel, liquid, granules and bait stations compared for New Zealand homes, why bait beats spray, and when DIY stops working.
The short answer
Yes, when it is slow. A good ant bait is eaten by the workers, carried back to the nest and shared with the queens and brood before it kills anything, which is how it reaches ants you never see. Gel suits cracks indoors, liquid suits busy sugar-feeding trails, granules suit nests outside, and a closed bait station keeps any of them away from children and pets. It is the same principle behind our ant control.
Do ant bait stations work?
They do, provided the ants feed from them and survive long enough to carry the bait home, and University of California guidance rates bait stations as the safest and easiest way for a household to bait. The catch is strength: ready-filled stations are often strong enough to kill the foragers near the station, which is fine for a small trail and weak against a large infestation.
For a big or stubborn problem, refillable stations holding a weak liquid bait are what that same guidance recommends, particularly for severe Argentine ant infestations, because a weaker bait keeps the foragers alive long enough to share it through the colony. A station also protects the bait from sunlight and from small hands, which is a large part of why it is the safer choice. Whichever you use, placement and patience decide the rest, and both are covered further down.
At a glance
Ant bait types compared
| Type | What it is | Best for | Where it goes | Watch out |
|---|---|---|---|---|
| Gel bait | Sweet or protein gel from a syringe or tube | Trails going into cracks and cupboards indoors | Small dots in cracks, hinges, behind appliances | Too much in one place; keep it off open benches |
| Liquid bait | Sugar solution with a slow-acting killer | Busy sugar-feeding trails, Argentine ants | In a refillable station on or beside the trail | Runs dry fast; refill it |
| Ready-filled bait station | Sealed station with gel or liquid inside | Small trails near children and pets | Flat, beside the trail, near the entry point | Often strong enough to kill foragers before they get home |
| Granular bait | Food-based granules with a slow-acting killer | Nests outdoors in lawns, beds and paving | Scattered near the nest or trail outside | Some granules are contact killers, not bait: read the label |
| Contact powder or granules | Kills ants that walk through it | Not a bait; little effect on the nest | Not on a bait trail | Kills foragers only |
| Borax and sugar (home-made) | A weak home liquid bait | Sugar-feeding trails indoors | Lidded container on the trail | Too strong and they stop taking it |
How ant bait works, and why it beats a spray
Ant bait is food with a slow-acting insecticide mixed into it. Foragers find it, recruit other workers to it and carry it home, where it is passed mouth to mouth through the colony, a process called trophallaxis, until it reaches the larvae and the queens. It has to be slow, because a bait that kills the forager on the spot never gets past the entrance of the nest.
Killing workers on their own achieves very little. University of California researchers note that as few as one in a hundred of a colony's foragers can bring in enough food to keep the queens and larvae going, so the ants you can see are expendable to the nest. A repellent spray does the opposite of a bait: it kills the ants it touches, leaves the colony alone and, with Argentine ants, makes the nest split, which we explain in why a repellent spray makes an ant problem worse.
Gel, liquid or granules: which ant bait suits which ant?
Gel suits small, precise placements indoors, in cracks, behind appliances and around cupboard hinges, wherever a trail disappears into the structure. Liquid sugar bait suits a busy sugar-feeding trail, the classic Argentine ant situation. Granular bait belongs outdoors, scattered near nests in lawns and garden beds, and is often protein- or oil-based for colonies that are feeding brood.
Sugar or protein. Offer a small dab of each and use whichever the ants take. Colonies change what they want with the season and the stage of their brood, and University of California guidance finds Argentine ants most drawn to protein in spring, when they are raising new offspring, and to sugar all year round.
Read the label for the word bait. Some granules sold as ant killer are contact insecticides that kill the foragers they touch and never reach the colony, which University of California guidance warns are easily mistaken for bait. This is where ant sand belongs: it is the name many New Zealand shops use for granular ant killer, and some products sold under that name are baits while others are contact killers, so the label is what tells you which.
Powders dusted along a trail are contact killers too, and they have no place on a trail you are baiting, because they kill the very workers you need to carry the bait home.
White-footed house ants are the hard case. Landcare Research notes that their workers do not pass bait on to one another, so it takes far more bait, at more points, to bring a nest down, and a single station rarely makes a visible difference.
What is the best ant bait in New Zealand?
The best ant bait is the one this colony eats. No product is best across every species and season, so rather than a brand, look for five things: the label says bait; it is slow-acting; the ants actually take it, whether it is sugar or protein; it suits the place, with gel inside, liquid on a busy trail, granules outdoors and closed stations near children and pets; and there is enough of it at enough points.
That last point is where most home baiting falls short. One station on a windowsill is right for a single trail from a single gap, and wrong for ants coming in along a whole side of the house, where several placements on every trail, inside and out, do far more than a stronger product. If the ants ignore a bait for a couple of days, move it closer to the trail or switch between sugar and protein before buying anything new.
Where to put ant bait, indoors and out
Put bait beside the trail rather than across it, as close as you can to where the ants come in, and outside along the trail and near the nest or the base of the wall. Keep it out of direct sun and rain where you can, never put it where a spray or a disinfectant has been used, and replace it as soon as it runs empty.
Indoors, the usual spots are the back of the bench where a trail meets the wall, under the sink where the pipes come through, the toe-kick of the kitchen cupboards and the frame of the window or door the ants use. Outdoors, bait along the foundations, beside paths where trails run and at the base of any shrub or tree the ants are climbing. With Argentine ants, bait mostly outside, because University of California guidance warns that indoor baiting can draw more of them into the house.
Do ant traps work?
Most products sold as ant traps are really bait stations, so they work in the same way and on the same conditions: a slow bait the ants carry home, placed beside the trail and left alone. A trap that only catches ants, such as a sticky card, removes some foragers and leaves the nest untouched, so it tells you ants are about and does little else.
Check the label before you buy: if it does not say bait, it is not going to reach the colony.
Ant bait, children and pets
Use closed bait stations anywhere a toddler or a dog could reach, put gel into cracks rather than on open surfaces, keep products in their original packaging and out of reach, wash your hands after placing bait, and follow the label. A closed station keeps the bait itself away from small fingers and noses while the ants can still get in.
If a child swallows ant bait, call the National Poisons Centre on 0800 764 766, which answers at any hour, and have the packet with you. If a pet eats it, call your vet. Whatever the packaging looks like, treat every ant bait as a poison.
Borax and home-made bait
Borax or boric acid dissolved in sugar water is a home-made liquid bait, and it works for exactly the same reason a bought one does: the workers drink it, take it home and share it before it kills them. It only works while it is weak, because a strong mix kills the foragers too quickly and the colony stops taking it. We have set out how weak a borax and sugar bait needs to be, and why.
When bait is not working, and when to call someone
Give bait about 5 to 10 days to show fewer ants and a few weeks to finish. If numbers have not fallen after two weeks, one of four things is usually wrong: the bait is too strong or the wrong food, it sits across the trail or near spray residue, the ant is the white-footed house ant and needs far more bait, or Argentine ants are refilling the house from next door.
Past that point, buying more products usually costs more than a visit. What we bring is identification, the right bait for what the colony is eating that week, and enough placements across the property to reach every nest, inside and out. Our page on professional ant baiting sets out how a treatment runs and what it costs, or you can request a visit and we will look at it with you.
Questions
Ant bait questions
How long does ant bait take to work?
Expect fewer ants within about 5 to 10 days and several weeks for the colony to be finished, according to University of California guidance. Numbers usually go up for the first few days while the workers recruit to the bait, which is a good sign. If two weeks pass with no change at all, something about the bait or where it sits is wrong.
Why are there more ants after I put bait out?
Because it is working. A forager that finds good food lays a scent trail back to the nest and brings others to it, so a bait the colony likes draws a crowd before it thins them. Leave the trail alone, keep the bait topped up rather than letting it run dry, and do not wipe or spray the line while they are feeding.
What kills ants immediately?
A contact spray, boiling water or soapy water kills the ants it touches straight away, and none of them reaches the nest, so the trail is soon back. That is fine for clearing ants off a bench. A bait is slower, but it is the only one of the four that actually reduces the colony producing them.
What will kill an ant's nest?
A bait the workers carry inside it. Pouring something onto a nest, whether boiling water or an insecticide, kills the ants near the surface, and the rest of the colony carries on deeper down or moves elsewhere. For a nest you can see in a lawn, a path or a garden bed, granular bait scattered nearby is the do-it-yourself tool, left for the workers to collect.
Can ants stop taking a bait?
Yes. It happens when the bait is too strong, when the colony wants protein and the bait is sugar or the other way round, or when spray has contaminated it. Landcare Research reports ants ceasing to feed on some baits, and nests fracturing after a dose that was not lethal. The answer is a weaker bait or a different food, not more of the same.
Sources
- UC Statewide IPM Program: Ants (Pest Notes)
- UC Statewide IPM Program: Ants in the home, quick tips
- UC Statewide IPM Program: Managing Argentine ants with baits
- Manaaki Whenua Landcare Research: Argentine ant control tools
- Manaaki Whenua Landcare Research: Technomyrmex jocosus (white-footed house ant) factsheet
- National Poisons Centre
More advice
Other things worth knowing
Argentine ants in Auckland: how to tell, and what actually works
How to tell Argentine ants from other Auckland ants, why their supercolonies refill a cleared house, when they peak, and what works against them.
Read this AntsHow to get rid of ants in the house
A practical order of work for ants in the kitchen, in the walls or nesting inside the house: find where they come in, bait them properly, then seal the gap.
Read this IdentificationTypes of ants in New Zealand, and how to tell which one you have
The ants in New Zealand homes and gardens by size, colour, smell and trail, which ones bite, why white ants are really termites, and what to do about fire ants.
Read thisNot sure what you are dealing with?
Describe it, or send a photograph. Identifying it correctly is our job, and it is what decides the treatment.