Ants are the most frequent and persistent pests encountered around homes and buildings. Besides being a nuisance, ants contaminate food, build unsightly mounds on our property, and cause structural damage by hollowing out wood for nesting. Species such as fire ants inflict painful stings, which can be life-threatening to hypersensitive individuals.
To most householders, all ants look pretty much alike. In truth, dozens of different species occur around homes and buildings, each having unique characteristics which may influence the method of control. In Australia about 3000 species of ants are known. In Brisbane, the most common house-invading ants include pavement ants, carpenter ants, acrobat ants, pharaoh ants, and odorous house ants. The latter species has become a particular nuisance in recent years, and will be discussed later in detail. Knowing which ant(s) you have often requires the help of an entomologist or knowledgeable pest control firm. Collecting a few of the non-winged worker ants in a plastic bag or vial will help with subsequent identification.
Dealing with ants can be very frustrating. This publication will help you control them, or at least know when it's time to call a professional. Recommendations pertain to all structure-invading ants found in Brisbane except carpenter ants, which are discussed in a separate publication.
At certain times of the year, ant colonies produce large numbers of winged individuals known as swarmers. These winged ants emerge from the nest to mate and establish new colonies. When a swarm of ants emerges inside a home, it's an indication that a nest is present within the structure. Fortunately, the success rate for swarmers establishing new colonies inside buildings is low. Nonetheless, an exodus of winged ants emerging indoors can be disturbing and often mistaken for termites.
Appearance of winged ants versus winged termites. Ouite distincly the pinched waist and elbowed antennae on the ant. Winged ants can be distinguished from termites by comparing certain features. Ants have a narrow (pinched) waist similar to wasps, whereas termites are virtually the same width from end to end. Ants and termites each have four wings; however, on ants the front wings are longer than the hind wings while on termites all four wings are of equal size and length. Finally, the antennae of ants are bent or "elbowed" whereas termite antennae are straight.
Ants build their nests in many different locations both inside and outside of buildings. Species nesting inside, or foraging indoors for food or moisture, tend to be the most challenging to control.
Ants Nesting Indoors
The advantage in using baits is that foraging ants take the insecticide back to the nest and feed it to the queen(s) and other colony members. As a result, the entire colony often is destroyed. Most baits sold to homeowners come pre-packaged with the insecticide and food attractant confined within a plastic, child-resistant container.
Baits are easy to use and often effective. Some of the more effective ant baits, sold in grocery and hardware stores.
Ants are rather finicky in their food preferences and may alter them throughout the year. If one bait product isn't attractive or doesn't seem to be working, try another. Optimal results usually require a sustained period of feeding, not just a brief visitation by a few ants. Professional pest control firms have a wider selection of bait products to choose from (e.g., Advance™, Maxforce®), and can usually provide relief when homeowner efforts are unsuccessful. Professionals also have a larger arsenal of sprays and insecticide dusts which can be effective against ants.
Ants Nesting Outdoors
When a below-ground nest is discovered, the colony often can be eliminated by spraying or drenching the nest location with a liquid insecticide. Large colonies will require greater amounts of liquid to move the insecticide throughout the network of underground galleries within the nest (using a bucket to apply the diluted insecticide concentrate is an effective method). Follow label directions for treating ant mounds, paying attention to precautions for mixing and application. Another effective and convenient way to control some species of outdoor and indoor-nesting ants is with a granular bait product. Sprinkle the bait in small amounts beside outdoor ant mounds, along pavement cracks, and other areas where ants are nesting or trailing.
Ant entry into homes can be reduced by caulking around door thresholds, windows, and openings where utility pipes and wires enter buildings.
In Brisbane, spraying or applying granular insecticides to the entire yard is not recommended, and will seldom, if ever, solve an ant infestation indoors. Whole-yard treatments also eliminate beneficial ants, which help to keep other damaging pests of lawns and gardens in check.
Odorous House Ants
The odorous house ant has become the most common and difficult ant species to control in Brisbane, and throughout much ofAustralia. The ant is small (3-mm), darkish, and forms distinct trails along outdoor and indoor surfaces.
Odorous house ants will nest in virtually every imaginable location. They commonly nest outdoors under pavement, stones, mulch, woodpiles, flower pots, and house siding, foraging indoors for food and moisture. Nests also occur indoors within wall cavities, appliances, potted plants, etc., especially near sources of moisture. The nests tend to be mobile; colonies relocate fast and often in response to changes in weather and disturbance.
This particular ant is difficult to control, especially by householders. The better baits to try are often syrupy ones. As with all ants, activity indoors can sometimes be reduced by removing ready access to food and moisture (water leaks, spillage, trash cans, pet food dishes, etc). Temporary relief can sometimes be had by wiping away the invisible odor trails with a kitchen cleanser or mild detergent. Do not disturb foraging trails, however, if you are using a bait. Caulking obvious ant entry points also may be helpful, along with trimming back shrubs and limbs touching the building. In nature, this ant feeds extensively on plant nectar and honeydew excreted by plant-sucking insects such as aphids.
When odorous house ants are the problem, homeowners may be better off calling a professional, although they, too, are challenged by this ant. Some products used by professionals can be effective, but are not available to the general public.
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