Commercial Ant Baits
These are designed to attract foraging ants. When the bait is taken back to the nest, it becomes contaminated. Baits only work if the area they are placed in is clean. Otherwise the ants will continue to feed on “real” food.
Sprays provide an immediate knockdown and can help deal with the infestation until the nest or source is eliminated.
Dusts, Powders and Granules
When placed in direct pathways, they are absorbed by ants and brought back to the nests for direct treatment of colonies. Some of these products can be used outdoors as barriers as well.
When dealing with ants, the sure-fire way to eliminate them is to find the nest. Queens lay eggs constantly, providing a steady supply of fresh ants. Getting rid of the nest and the queen should solve your problem. To locate a nest, place a dab of jelly or peanut butter out where you’ve seen the ants. Watch the ants, (most are more active at night) and see where they go. It's likely that they are leaving the house for a nest outdoors. Treat the perimeter of the house to keep them out or treat the nest itself. The area along the foundation is relatively protected from the elements and a good place for ants to nest.
Ants on landscape plants or houseplants often coincide with the presence of aphids. Check houseplants for ants before bringing them indoors.
Anthills in the lawn can be treated with ant-specific pesticides. Some choose to apply boiling water to anthills. While boiling water is a good remedy, it takes a lot of water to kill a good-sized anthill and it kills everything it touches, including grass.
If your problem is carpenter ants, control is a little different. Carpenter or wood-boring ants will be detected by the presence of frass. Frass is a deposit of sawdust and other tiny debris left near the nest. Carpenter ants prefer moist wood (which may also indicate a moisture problem). They do not respond well to baits. Find the nest and apply the appropriate insecticide.
When using pesticides, make sure you choose and use them wisely. Read the label to see if the product is restricted to indoor or outdoor use. Follow all manufacturer's instructions.