ControlThe Black House Ant ( Iridomyrmex glaber) and White Footed House Ant ( Technomyrmex albipes) are small black ants 2.5-3mm long. They nest in rockeries, near or under paths, in wall cavities and in potted plants. They eat a variety of foods and are attracted to sweet substances. They give an annoying bite but do not sting.
Meat Eating Ants ( Iridomyrex purpureus) are 12-14mm long and are red/purple and black. They like sunny areas and often build large gravelly mounds. They feed mainly on animal material, and honeydew. They can bite but do not sting and rarely enter houses.
Sugar or Carpenter Ants ( Camponotus species) are 5-15mm long, they have orange/brown bodies, black abdomens with an orange/brown band and black heads. They nest in decayed moist wood or sometimes in the soil. They feed on dead and live insects, honeydew, household waste and are attracted by sweet food. These ants do not sting and rarely enter houses.
Bulldog or Bull Ants ( Myrmecia species) have red bodies and black abdomens. They are about 20mm long. These ants can cause a painful sting. They rarely enter houses and are usually found in the garden or bushland areas.
Argentine Ants ( Iridomyrmex humilis) Are about 3mm long and are light to dark brown in colour. They do not have the formic acid smell ants usually have and they are very active in their movements.
White Ants are not a true ant and are correctly called "termites."
![]() |
|
Close-up photo of a Fire-Ant |
Chemical control
Chemical control may be warranted if a persistent infestation of ants causes a
problem/nuisance. We prefer low-toxic chemicals or ant baits.
Types of
Ants
To most householders, all ants look pretty much alike. Dozens of different
species occur around homes and buildings, each having unique characteristics,
which may influence the method of control. In Sydney, the most common
house-invading ants include black ants, white-footed ants, carpenter ants,
pharaoh ants, fire 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.
Ant Characteristics
Ants are social insects, which live together in cooperative, intermingling
colonies. The colonies may range in size from hundreds to millions of
individuals, depending on the species. Within each colony are different types of
individuals, each with a specific function. All ant colonies contain one or more
queens, whose primary role is to lay eggs. The eggs hatch into white, grub-like
larvae that later transform into adult "worker" ants. The workers feed and care
for the queens and developing brood, and are the ones seen foraging for food and
water, often at great distances from the colony. Ants lay down invisible odour
trails, which the workers follow between food and the nest. In many species, the
trail of ants is distinct enough to be followed back to the nesting location, or
to where the ants are entering from outdoors.
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.
The Difference between Ants and Termites
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.
Ant Control
The mistake most people make when attempting to control ants is only
spraying the ones they see. This approach usually fails because the ants seen
foraging over exposed surfaces is only a small portion of the colony. Typically,
there will be thousands of additional ants including one or more egg-laying
queens hidden somewhere in a nest. Eliminating queens and other colony members
within nests is often the key to effective ant control.
Ants Nesting Indoors
Buildings contain many favourable hiding and nesting sites for ants.
Preferred sites include spaces behind walls, cabinets, and appliances; behind
window and door-frames; and beneath floors and concrete slabs. Most of these
areas are hidden, making it difficult to determine their precise location. When
the location of the nest cannot be determined or is inaccessible, insecticide
baits often are a good option, especially for homeowners.
Consider Using Ant Baits
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. Place the baits next to wherever ants
are seen, preferably beside ant "trails" (invisible odour trails which worker
ants follow between food and the nest). Do not spray other insecticides or
cleaning agents around the bait stations, as this will deter ants from feeding
on the bait. Initially, you should see an increase in the number of ants around
the bait station -- DO NOT SPRAY THEM. This indicates that the ants are feeding
on the bait and transporting the insecticide back to the nest. Ant activity
often will subside in a matter of days as the number of ants in the colony
declines. Continue to place additional baits wherever ants are seen.
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.
Ants Nesting Outdoors
Ants noticed inside the home may actually be nesting outdoors in the yard.
Try to trace the ants back to the point where they are entering from outside.
This may be along a window sill, beneath an entrance door, or where the exterior
siding meets the foundation wall. Ants usually prefer to trail along lines and
edges. When tracing ant trails indoors or outdoors, pay particular attention to
cracks, seams, and edges created by baseboards, the tack strip beneath perimeter
edges of carpeting, mortar joints, the foundation- siding interface, etc. Nests
often will be located in the ground, marked by a mound or anthill. Other times,
the nests will be concealed under mulch, gravel, stones, landscaping timbers,
pavement, or beneath the grass edge adjoining the foundation wall of the
building. Some kinds of ants prefer to nest behind exterior siding or wood trim
that has been damaged by moisture. While it takes patience to locate an ant
colony outdoors, results will be more rapid and permanent than if you only spray
where ants are seen trailing. One way to entice ants to reveal the location of
their hidden nest(s) outdoors or indoors, is to place small dabs of honey or
jelly on an index card, etc., next to where ants are observed. After the ants
have fed, they will head back to the nest.
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.
Physical Ant Control
Caulking around door thresholds, windows, and openings where utility pipes
and wires enter buildings can reduce ant entry into homes.
Treating under doors and along foundations can reduce ant entry from
outdoors.
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 Sydney, and throughout much of Australia. The ant is small,
darkish, and forms distinct trails along outdoor and indoor surfaces.
It is often mistaken for the pavement ant, which can readily be controlled
with most baits. The most accurate diagnostic difference, visible under
magnification, is the absence of a noticeable node or "bump" along the
constricted area between thorax and abdomen of the odorous house ant. Odorous
house ants emit what's been described as a rotten coconut or pine scent when
crushed with a finger and sniffed.
Odorous house ants will nest in virtually every imaginable location. They
commonly nest outdoors under pavement, stones, mulch, woodpiles, flowerpots, 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.
Ants forage indoors for food and moisture. Odorous house ant colonies tend to
have numerous, egg-laying queens and the primary colonies may split into smaller
ones for no apparent reason. Ants foraging indoors feed on all manner of foods,
ranging from the rubbish bin to the cereal bowl.
This particular ant is difficult to control, especially by householders. 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). Wiping away the invisible odour trails with a kitchen cleanser or mild
detergent can sometimes have temporary relief. Do not disturb foraging trails,
however, if you are using 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 this ant, too,
challenges them. Some products used by can be effective, but are not available
to the general public.
CAUTION! Pesticide recommendations in
this article are registered for use in Australia only! The use of some
products may not be legal in your state or country. Please check with your local
county agent, pest control firm or regulatory official before using any pesticide mentioned in this
publication.
Of course, ALWAYS READ AND FOLLOW LABEL DIRECTIONS FOR SAFE USE OF ANY
PESTICIDE!