Managing ants with baits

Ant baits contain insecticides mixed with materials that attract worker ants looking for food. Baits are a key tool for managing ants and the only type of insecticide recommended in most situations. Ants are attracted to the bait and recruit other workers to it. Workers carry small portions of the bait back to the nest where it is transferred mouth to mouth to other workers, larvae, and queens to kill the entire colony. Bait products must be slow-acting so that the foraging ants have time to make their way back to the nest and feed other members of the colony before they are killed. When properly used, baits are more effective and safer than sprays.

Baits are available in several different forms. For residential users, the most readily available forms are solids or liquids that are prepackaged into ant stakes or small plastic bait station containers like those in the photo above. These products are easy to use and are quite safe if kept away from children and pets. Some products dry up rapidly and must be frequently replaced to manage a large population. A few boric acid products are liquids that are poured into refillable containers or applied as drops on cards.

Reusable bait stations or dispensers are more useful than prepackaged baits for difficult ant problems. Reusable stations can be opened, checked, and refilled as needed. This is particularly important for liquid baits, which may be rapidly consumed or dry out. Some stations have removable cups that can be filled with two or more types of baits to offer ants a choice. Bait stations protect baits from photodegradation and disturbance by children. Some types of bait stations can be permanently installed into the ground or attached to outside walls or pavement in areas around schools or other buildings where ants are a frequent problem. The bait stations may be hidden in mulch so they aren't immediately visible to children or pets.

Gel formulations of pesticide baits are packaged in small tubes. They are applied in small cracks and crevices where ants are entering. Gel products are now available to home users as well as professionals and can be a useful tool in an IPM program.

Ant baits contain carbohydrates (e.g., sugars), proteins, oils, or a combination of these as attractants along with an active ingredient (toxicant). Different attractants are more effective against different species of ants and at different times of the year. In the case of Argentine ants, sweet baits are attractive year-round. Protein baits are attractive to Argentine ants primarily in the spring. However, other ant species such as thief ants and Pharaoh ants prefer protein or greasy baits year-round. Fire ants prefer baits containing oils. See Common household ants for information on food preferences. Offering a small quantity of each kind of bait and observing which one the ants prefer is a good way to determine what to use.

Look for the active ingredient listed on the label of bait products. Some examples of active ingredients include hydramethylnon, fipronil, boric acid (borate or various forms of sodium borate), and avermectin B (abamectin). The Common ant baits table below lists some common ant bait products organized by active ingredient. Bait products are constantly being improved. Look for new active ingredients and improvements to current products. Avoid products packaged as granules that contain the active ingredients cyfluthrin or permethrin. Although these products may be mistaken for baits, they are actually contact insecticides that rapidly kill foragers and don't control the colony. Likewise, bait stations with propoxur or indoxacarb aren't very effective, because the active ingredient is too fast-acting.

To improve bait effectiveness, be sure to remove any particles of food, residues of sweet liquids, or other attractive material from cracks around sinks, pantries, and other ant-infested areas. For the most effective and economical control, use baits only when there is an ant problem. Treatments made in late winter and early spring when ant populations are just beginning to grow will be most effective. Ant preferences can change throughout the year; to increase your success rate, set out different formulations of various bait products in a single baiting station, giving ants a choice. Don't use any insecticide sprays while you are using baits, and check and refresh bait stations regularly. Baits can dry up or become rancid and unattractive over time.

Use baits primarily outdoors. Use indoors only if there is a serious infestation and you can't find the spot where ants are entering the building: otherwise you could attract ants indoors. Outdoor baits draw ants out of buildings. Place bait stations where ants can easily find them, but avoid placing them in areas that are accessible to pets and small children. Place baits near nests, on ant trails beneath plants, or along edges where ants travel. Space them every 10 to 20 feet outside around the foundation and at nest openings, if they can be found. Effectiveness of baits will vary with ant species, bait material, and availability of alternative food. To achieve wide distribution of the bait so the entire colony will be killed, the bait toxicant must be slow-acting. Control with baits isn't immediate and may take several weeks or more to be complete.

Bait stations for Argentine ants

Currently the most effective baits available to consumers for Argentine ants are the borate-based baits. Prepackaged bait stations usually contain 5.4% borate. They can be effective at killing foragers in the home but are less effective at managing major infestations, because foragers are killed before they can bring the bait back to the colony.

Liquid borate products with a lower percentage of active ingredient (0.5 to 1.0% concentration in a sugar-water solution) will have more impact on the colony, although it may take several days to a week to see results and they need to be used in larger, refillable bait stations. Products with the lower concentration of borates (e.g., Gourmet Liquid Ant Bait) are registered for home use but are difficult to find in stores and may have to be ordered online.

Several refillable bait stations are available including the Ant Café, Antopia, Ant-No-More, and KM AntPro. University of California research with the KM AntPro dispenser has shown that it can be effective when properly installed and maintained outside the home. Usually at least one dispenser is installed around each side of a house and placed in shady areas where ants trail. Stations must be checked regularly and refilled as necessary. For more information about installation and maintenance, see the video on refillable bait stations.

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Common ant bait products

This is not intended to be a complete list of all available products. Effectiveness varies according to ant species and product. Starred (*) products may be available for professional use only.

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WARNING ON THE USE OF CHEMICALS

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