Ant Treatment

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Proper procedures for ant control in and around homes or other buildings depend greatly on the species of ant involved, the extent and nature of the infestation, and the location of the nest(s) used by the infesting species. Proper identification of the ant species in each situation will help determine where to begin the search for the source of the infestation and whether there may be multiple nests for separate colonies or satellite nests for one colony. 

The most efficient and effective way to control ants in and around homes or other structures is to locate and directly treat with an insecticide-liquid or dust formulation all nests located inside or outside premises. Other insecticide formulations or applications such as many effective baits and perimeter sprays with repellent (pyrethroid) or non-repellent active ingredients labeled for ant control have their place in ant control programs. But finding and directly treating as many nests as possible is the quickest and most certain way to solve the problem. Therefore, PMPs need to become skilled at finding all ant nest locations in and around infested premises.

Fortunately, many insecticide active ingredients will effectively control any and all types of ants when the nests are found and are accessible to treatment. Unlike German cockroaches, resistance problems are not an issue with ants. However, for some pest ant species and for many infestation situations encountered in the field, it may not be possible to find or directly treat all (or maybe even any) of the nests. In such cases, baits and residual applications must be relied upon. Effective ant treatment will usually require follow-up inspections and insecticide applications. In areas where environmental conditions favor continuous ant presence and the ability to reinfest, ongoing ant pest management programs will be needed to provide the level of control or suppression that customers desire.

The first step in ant control in or around homes or other buildings is to conduct a thorough inspection of the premises to determine which species are present (one or more may be involved) and if possible, all the nest locations. In addition to obvious nest locations such as mounds in soil or presence of ant swarms or other aggregations, focus should also be on the presence and location of any and all moisture sources that are available to the ants. These can include leaking irrigation sprinkler heads, water meter or control valve boxes sunken into the soil, moist areas underneath potted plants, in mulched areas or under heavy and matted vegetation around the foundation, clogged rain gutters at the roof line, condensation on or dripping from any chilled surfaces, or other sources.

Once the sources of moisture being utilized by the ants are determined, we can look for foraging trails used by the ants. These will usually be along edges or other structural guidelines present.

Sometimes, a survey program with non-toxic baits is necessary to determine where ants are nesting and foraging. Useful survey bait items may include a simple sugar solution, honey or honey/water solutions, jelly, peanut butter, bits of fresh meat, freshly killed insects, or bacon grease. More than one type of item is often used to ensure a response by the ants.

Many survey bait locations may need to be checked and possibly moved on repeat visits over several days in some cases. A diagram of the premises and notes of ant sightings should be made to guide proper and thorough treatments at a later stage in the control program.

Once the feeding preferences of the ants are determined, the type of insecticide bait food-base attractant that should be accepted is also identified. Adequate amounts and placements of the appropriate bait formulations can then be offered.

If an ant colony or colonies are established within the structure, killing the exposed workers seldom gives significant or permanent relief because the foraging workers are usually less than 15 percent of all the ants present in the colony. The queen or queens in the nest(s) will also continue to produce more workers.

A chemical barrier or perimeter treatment may be effective for some ant species nesting outdoors that are invading the building for food, but it may not be very effective at all for other species. Regardless, this barrier will be only temporary because workers from the nest or from other nests will again invade the building when the chemical residue becomes ineffective.

Colony eradication will provide longer-term relief, so it is important to remember that the first priority of ant control is to locate and directly treat the nest(s), to eradicate them through effective use of baits if necessary, or to use one of the newer non-repellent residual insecticide sprays that can provide general suppression of ants and often colony kill (as contaminated workers return to the nests).

In the case of pharaoh ants, it is very rare that the professional is able to locate and gain direct access to the usually numerous nest locations. Finding carpenter ant nests may also be very difficult and time-consuming, even when freshly killed insects are used as survey baits. The task may even require some carpentry skills to open void areas to locate the colonies and allow effective insecticide treatment. Specific management procedures for carpenter and pharaoh ants will be discussed separately following the discussion of general recommendations for managing other ant species in and around homes or other structures.