Ants, like many insects, can be found throughout the landscape. Their biology, behavior, and pest status vary by species, but ants also play important roles in a healthy environment. They create tunnels and galleries in the soil, which brings air and water to plant roots, and move seeds underground. Ants consume organic matter that would otherwise rot. Ants ARE food for many animals, such as birds, while some ant species are natural predators of other pests. For example, common field ants that inhabit grassy areas prey upon grubs and caterpillars that damage turfgrass.
But ants can also be pests, difficult to control and prevent even with the most aggressive pest management action: the application of residual, long-lasting pesticide sprays. When conventional approaches like spraying fail to get desired results, or in cases where spraying pesticides is not wanted or not allowed, ant baits can help get the problem under control.
Baits work well for managing ants because ants are social insects. The colony depends on foraging workers to bring back food for the queen(s) and larvae. When a toxic bait is appealing to foragers, they will bring back as much as they can to the colony and feed bait to what is considered the “heart” of the colony – the larvae. Ideally, this results in collapse of the whole colony.
Here, we describe the types of baits available and how best to use them for good ant control. We lead with baiting strategies because your approach will determine the type of bait you use. Always Read the Label on any pesticide product and keep in mind that the label on a pesticide container is federal law. Using any pesticide in a manner not described on the label is illegal. Some baits are only available to licensed pest management professionals.
- If the main ant colony can be located, observe ant movements and place baits near colony activity - along trails, edges and walls. Ants use and reuse routes from outside to inside that are convenient, such as wires and cables, branches touching the structure, and even pathways through the lawn. Indoors, they often trail along the wall base or edge of a countertop.
- Do not clean up or spray pesticides where you see ants trailing if you want to use a bait. Ants dot the trails with chemical scents, or pheromones, to give their nest mates directions to the food.
- Bait stations are helpful for preventing spills and evaporation of liquids and gels, for containing granular baits, and for restricting access to ants only.
- Place baits in areas hidden from children and pets.
- Bait outside to lure ants out of the building or home, as long as the weather is warm enough for insect activity.
- Let the ants party! It will take time for the bait to work - one to a few days to reduce foraging – and it could be several weeks before the colony is killed. Be generous! Keep offering bait and be patient. Baiting is the most effective way to get to the heart of the colony, where the larvae and queens live.
Types and formulations of baits
Ant baits are sometimes formulated as sweet liquids containing small amounts of insecticide, commonly boric acid. Liquid baits are attractive to ants when water and sugar are scarce during hot and dry weather or when temperatures are cold enough to freeze available water. Liquid is consumed by foragers and brought back to the nest, where it is regurgitated to feed larvae and queens, resulting in transfer of the toxins to the heart of the colony. Liquid baits need to be placed inside bait stations to avoid spills and evaporation.
Formulated to taste like honeydew (which is the sugary excrement of sap-feeding insects, like aphids), gel baits are highly attractive to ants when sugars are scarce (late fall, winter, early spring). Like liquid bait, ants can easily consume and transport gels back to the colony. Gel baits are attractive to carpenter ants and other sweet-loving ants. Gel baits should be used indoors. When used outside they must be placed inside a bait station for protection from overly dry and wet conditions.
Proteins and fats are formulated into paste-style baits that resemble peanut butter (keep it away from kids and pets!). They are applied the same way as gel baits and are best used indoors or in bait stations. If ants are not attracted to sweet baits, protein/oil past baits may be more effective.
Designed to be carried back to the nest, rather than ingested on the spot, granular baits offer a solid food-toxin combination that may contain carbohydrates, fats or proteins, plus insecticide. They are designed to be used mainly outdoors but may be used in combination with liquids, gels, and pastes. Granules of bait come in different sizes to be attractive to different sized ants. Large granules are used for carpenter and field ants, and fine granules should be used for tiny pharaoh and thief ants.
Many over-the-counter baits are available in pre-loaded plastic bait stations that are usually circular with openings around the edge. Although inexpensive and easy to use, these baits are not as attractive as liquid, gel and paste baits.
Ant food preferences change seasonally to adjust to the nutritional needs of the colony. Ants have three main food preferences, carbohydrates/sugars, oils/fats, and proteins. To determine what type of food the ants are looking for, you can place a dab of honey or mint apple jelly and peanut butter onto a card, paper plate or on the inner wall of a plastic cup. Place the card or cup in an area known to have ants, inside or outside. Check within 15 minutes to see if the ants have congregated on one of the foods. If ants surround the sweet food, use a gel or liquid. If they prefer peanut butter, use a paste formulation with protein/fats.
Ant baits work for indoor ant infestations, but are most useful when food is not abundant outside. This happens when plants and insects are dormant over the colder months. Once plants grow and insect activity increases outside baits can be harder to use. Ants tend to forage food waste or spills before baits, so sanitation should be the first step. Make sure the area is clean and garbage cans rinsed out and secured. Houseplants can also be a source of honeydew when scale insects are present. Clean the surface under and around houseplants if you see ants there.
Patience is a requirement when dealing with America’s #1 pest. With a little investigation into the problem, proper identification and colony location, baiting can be a very effective tool that lasts for months.