How Long Does Terro Ant Bait Take to Kill Ants?

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Terro Liquid Ant Bait is a sweet liquid containing sodium tetraborate decahydrate, better known as borax. The bait kills individual ants within 48 hours after they consume it. During that time, an exposed ant carries the bait back to the nest and spreads it to other ants, killing them as well. Large nests may take several weeks to completely eradicate.



Terro ant baits wipe out individual ants within 48 hours and small nests in days. A large colony that contains thousands of ants and several queens may require several weeks before the nest collapses.

Types of Ants Terro Kills

Terro ant bait is formulated for sweet-eating ants, including Argentine ants, acrobat ants, big-headed ants, cornfield ants, crazy ants, ghost ants, little black ants, odorous house ants, pavement ants, pharaoh ants, and white-footed ants. Some species, particularly Argentine ants and pharaoh ants, are difficult to eradicate completely with baits because of their extremely large colony size. Terro Perimeter Ant Bait Plus products are formulated for carpenter ant control in addition to the sweet-eating ants mentioned above.


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Why It Works

The Terro Ant Bait products rely on colony behavior. Ant colonies consist of one or more queen ants, who lay hundreds or even thousands of eggs, but never leave the nest. Worker ants take care of the developing eggs, while other workers forage for food and bring it back to the queens and nursery workers.


Ant bait smells like food, but contains poison. Workers find it and bring it back to the nest before the poison kills them. There are several types of delivery methods, from the plastic pre-filled Terro Liquid Ant Killer II Baits for indoor use to the Outdoor Liquid Ant Baits and Outdoor Liquid Ant Bait Stakes, which are intended for use around the foundation of your home.

How It Kills the Nest

The borax in Terro ant bait is an acid that damages ants' digestive systems and weakens their exoskeletons when it sticks to the tiny hairs on their legs. Worker ants, mistaking it for food, feed it to other workers in the nest and, more importantly, to the queen. Once the queen in a colony is poisoned and dies, she can no longer lay eggs to replace the workers, which are also dying of the poison. The colony eventually collapses.


When to Remove the Bait

A small ant colony may succumb to Terro ant bait in a couple of days, while a colony numbering in the hundreds of thousands may take weeks to collapse. As long as ants are coming to the bait station, the colony is still at least partly functional and you should keep the bait station stocked with liquid ant bait. When no ants visit for several days in a row, you can remove the bait station. Be ready to replace it immediately whenever ants return.


Cautions When Using Terro Products

Keep all Terro products out of reach of children and pets. Do not use in food preparation areas. While technically not toxic to humans, the borax in the bait can cause eye and skin irritation and gastric distress if ingested. Consult your health provider, poison control center or veterinarian if a child or pet comes in contact with bait.


After placing the bait inside and/or outside of your home, wash your hands and the scissors used to open plastic bait stations thoroughly with hot water and dishwashing liquid. When the bait station is empty, place it in the trash. Don't rinse the container or wash any remaining bait down the drain.




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