If you haven't already realised by now,
I live in the good old U.K. where, we don't suffer from carpenter ants,
at least I have never heard of any. But the number of requests I get
from the U.S.A. about the problem are many, so I thought that I had
better cover the subject in these pages...
ants are among the largest species that you will find in the States.
Like other ant species, carpenter ants are social, i.e, they live in
a colony and have several "castes" or adult forms that perform different
jobs in the colony. The queen usually reaches 9/16 inch in length. There
are several sizes of workers that range in size from 1/4 to 7/16 inch.
All of these ants are adults regardless of their size, but only the
queen produces offspring in the nest. Immature ants (larvae) are white,
legless, and maggot-looking in appearance. They remain in the nest and
are fed by the workers ( which are split in to "major"and
"minor"workers ). The larvae develop into pupae, which are
tan and capsule-shaped. Eventually, new adults emerge from these pupae.
Adult ants will vary in colour depending upon the species. The black
carpenter ant (the one we are going to concentrate on), is the species
that most commonly nests in homes, and is primarily black in colour.
Other carpenter ant species may be more reddish-brown to yellow in colour.
the spring, carpenter ants swarm, i.e.,winged adults emerge from the
colony. The swarmer's sole purpose is reproduction (after mating he
dies). Shortly after mating, the female (queen mated for life) loses
her wings and searches out a cavity in wood or soil and each lays 15
to 20 eggs in 15 days.
egg stage takes about 24 days, larval stage 21 days and pupal stage 21
days or about 66 days from egg to adult at 70 to 90 degrees F. Cool weather
may lengthen this period up to 10 months. During the first brood, larvae
are fed entirely by a fluid secreted from the queen's mouth where she
does not take food, but uses stored fat reserves and wing muscles for
her nourishment. The few workers emerging from the first brood assume
duties of the colony, collecting food, excavating galleries to enlarge
the nest and tending the eggs, larvae and pupae of the second generation.
Workers regurgitate food for nourishment of the developing larvae and
queen. She has few duties except to lay eggs.
later generations, workers of various sizes are produced (polymorphism)
into major and minor workers, that are all sterile females. Larger "major"
workers guard the nest, battle intruders, explore and forage for food
while smaller "minor" workers expand the nest and care for the young.
Workers, when disturbed, carry off the larvae and pupa, which must be
fed and tended or they die. After 3-6 years, the colony will contain 2000-3000
workers, and will start to produce swarmers.
swarmers are actually produced in the autumn, but they wait until the
following spring to emerge. In a mature colony, there is usually one
queen with 200 to 400 winged individuals produced as swarmers. Workers
have strong jaws and readily bite (sharp pinch) when contacted. Swarming
is not the only means for carpenter ants to produce new nests. "Satellite"
colonies may be formed by workers that move out of the main nest, carrying
larvae and pupae with them. Eventually, these secondary colonies produce
their own reproductives.
of an Infestation:
are several indications of an infestation:
appearance of swarmers indoors is a likely indication of a nest in or
under the house (see picture below). Winged ants will emerge from around
baseboards, window casings, vents or other openings in floors or walls,
and will often congregate around windows. Swarmers found outdoors on
porches, siding or around windows are merely a sign of a nearby colony,
which is most likely located outdoors. However, it is well worth the
effort to inspect your home for other signs of ant activity.
excuse the colours in the above drawing...a little bit of artistic licence...but
it does show the difference between flying ants and flying termites...OK..!
in early spring, worker ants will often be found foraging for water around
bathroom/kitchen sinks, dishwashers or showers. Foraging activity is usually
greater at night when the lights are off, but you will find ants during
the daytime, as well. In some cases, you may be able to trace the insects
back outdoors where they are travelling to and from a nearby nest. With
extensive foraging, your will find trails that the ants maintain clear
of debris. These trails may extend up to 300 feet from the nest.
Camponotus ligniperda (another
type of Carpenter ant)
mature colonies infesting a house, you can actually hear rustling or gnawing
sounds coming from the wood or void where they are nesting.
the ants expand their nest, they throw out piles of fiber-like wood debris
and frass (fecal material). Debris with a dark appearance is likely an
indication of decaying wood, and can be used as a clue in searching for
the nest. The frass may have a sawdust-like appearance, but will also
contains the remnants of ants and other insects on which the colony has
above shows various samples or graphic illustrations of the difference
between frass and fecal pellets (which come from termites).
that is damaged by carpenter ants may have slit-like openings through
which the ants expel the sawdust and frass (see picture below). The galleries
will usually follow the wood grain, with the softer "springwood" portion
of the annual rings being excavated first. Tunnels through the harder
summerwood connect these galleries. The gallery walls will be relatively
smooth, resembling drywood termite damage. However, the galleries of drywood
termites are usually filled with small, hard, seed-like fecal pellets
that do not resemble the wood fibre debris that carpenter ants remove
from their galleries. Wood damaged by subterranean termites also has excavated
areas, but the gallery walls have a coating of a mud-like fecal material.
and Feeding Habits:
termites, carpenter ants do not eat wood; they tunnel through wood while
building or expanding their nests. Typical outdoor nesting sites include
tree holes, tree stumps, logs, standing dead trees, and planter boxes.
When conditions are suitable, carpenter ants may establish nests indoors.
Typical indoor nesting sites include structural wood, wall voids, attic
areas, insulation (foam or fibreglass), hollow doors, window/door casings,
voids beneath kitchen/bathroom cabinets, as well as hollow beams (e.g.,
decorative beams that may cover pipes or girders. In the case of carpenter
ant species that nest in existing cavities, the workers may subsequently
invade and damage nearby structural wood while expanding their nest site.
Looking at the sawn tree and the inside of a stud partition below gives
some idea of the damage that can be done.
ants prefer wood with a moisture content of 15% or higher, so the problem
is often associated with moisture. The ants often invade homes through
cracks and crevices in the foundation masonry, around windows and doors,
through foundation, as well as heating/AC vents. They may travel along
tree limbs or shrubs that touch the siding and roof, gaining access to
attic and roof space areas. Telephone, electric and cable TV lines also
provide ready means of entering the home.
primary food of carpenter ants is honeydew, the sugary secretions of certain
plant-feeding insects, such as aphids and scales. For that reason, worker
ants are often found travelling up tree trunks and on to limbs in search
of honeydew on the leaves. The ants will also feed on plant secretions
and fruit juices, as well on the remains of insects, including dead members
of their own colony. When the ants invade homes, they usually seek out
sweet items, such as sugar, but they also will feed on fats, grease and
meats. Water is also important to the ants. Outdoors, you will often find
ants collecting water dripping from water spigots, gutter downspouts or
air conditioner drain lines. Indoors, the ants are often seen near sinks,
bathtubs and dishwashers.
there are trees, stumps of trees or other wood items in and around the
home, there is always the potential for carpenter ant infestation. However
there are important steps that can be taken to prevent carpenter ants
from becoming a problem. Prevention starts with common sense and a thorough
inspection of the property and NOT with a monthly or whatever period application
of gallons of insecticide. It's alright to use insecticide in the correct
place at the correct time, but some guys think they have a bottle of "BRUT"and
splash it on all over. Proper maintenance of the property and surroundings
greatly reduces the risk of infestation. The KEY point to remember is
that carpenter ants are usually associated with moisture, particularly
where wood is involved.
- Check for moist, soft or rotting
structural wood. Pay particular attention to:
Attics, roof edges, eaves and gutters.
b. Flashing around chimneys, porch or deck roofs.
c. Porch roofs, railings and columns.
d. Door and window frames.
e. Flat roofs are particularly vulnerable if not maintained properly.
gutters and downspouts clear of debris.
outdoor water taps/spigots or other plumbing leaks that will definitely
attract foraging ants.
proper drainage around the property.
wood must be in direct contact with soil or masonry (e.g., when installing
landscape timbers, porch columns, decking, fencing, etc.), use the correct
type of pressure treated timber, sometimes known as tanalised timber.
cracks to the foundations, these will provide a 14 lane carriageway
for ants to gain access, termites as well.
the crawlspace dry and well ventilated. A properly installed vapour
barrier will help.
stack firewood on the porch and deck, or up against the sides of the
house itself or the garage (remember they have satellite colonies).
Stack firewood up off the ground, it will make inspection easier and
will also help prevent rodents from harbouring in this type of area.
tree limbs and shrubs pruned well back from the property. This will
also help prevent damage to the walls and roof, as well as reduce moisture
problems, and help keep ants from getting onto the roof, then into the
roof space, etc., etc., etc.
nearby trees which are in poor health or dead or rotting, remember the
picture above, the main colony could be in an old tree stump and this
colony could splinter into satellite colonies which will travel 300ft.
is important to remember that finding carpenter ants foraging inside your
home does not necessarily mean that they are nesting indoors. Do
not panic and do not resort to spraying insecticides indoors where
you see ants. Although spraying stops ant foraging for a while, it only
serves to detour them elsewhere (possibly elsewhere indoors) and they
will likely return when the chemical residue is gone. More importantly,
you may be delaying the inevitable discovery that the ants are actually
damaging your home. The first step in controlling carpenter ants is to
determine if they are nesting indoors. Spraying your foundation with any
of the common insecticides, such as chlorpyrifos (Dursban) or diazinon,
may keep foraging ants away temporarily, giving you a clue as to the source
of the ants. If ant activity continues at about the same level, then you
may very well have an indoor infestation. As an alternative to spraying,
you can try baiting the ants outdoors. Put small amounts of honey mixed
in water into bottle caps and place them along the foundation. Peak carpenter
ant activity occurs at night, so check these baits after sunset. Try to
track the ants as they move away from the baits and back to their nest.
Keep in mind that carpenter ant nests may be as much as 300 feet from
where you find foraging ants, so tracking them can be very difficult.
The main purpose of this baiting is to see if the ant trail leads. If
the ant trails move away from the house, you can use one of the control
methods mentioned below for outdoor infestations. If the ants appear to
be nesting indoors, the next step is to carefully inspect for likely nesting
sites. Concentrate first on those areas around your home that are most
vulnerable to moisture problems. Probing the wood with a screwdriver is
a good way to uncover damage by a number of wood-destroying pests, including
carpenter ants and termites. Careful inspection of the attic and crawlspace
are important. Because of the time-consuming and tedious nature of a thorough
inspection, you may want to enlist the help of a pest control company
that has the experience and the ability to quickly find and eliminate
infestations - Ant baits, particularly those containing hydramethylnon,
sulfluramid, avermectin or boric acid, can be effective if the ants are
foraging for food. If the ants are gathering around water sources (e.g.,
a sink), they may not be attracted immediately to the bait. In general,
baits are the best approach to dealing with ants. They are more effective
in the long term and are less hazardous (compared to sprays) when used
properly. However, they may require a week or more before ant activity
declines. You must be willing to tolerate some ant activity to give the
foragers enough time to carry the bait back to the nest where it will
be fed to the larvae, other workers and to the queen. Do not spray areas
where you will place the bait; otherwise, the ants will avoid these areas
and not pick up the bait. If ant activity continues at about the same
level for several weeks, then you need to take additional steps to deal
with the problem. Before you do any spraying, you should first determine
the extent of any structural damage caused by the ants. If the damage
is severe, repairing and/or replacing wood (and subsequently removing
the nest) may be more important than any treatment, and may solve the
problem in the process. If damage is minor, then you can use of a pesticide
that is labelled for application to wood to eliminate the nest. Effective
control often requires the injection of insecticidal dusts or sprays into
voids or into the nest. These treatments are complex and may be too difficult
for the average person to carry out safely. Contact a pest control professional
for help in these situations.
treatments - If the ants are foraging from an outdoor nest, then a
perimeter treatment may do the job. Spraying outdoors with Sevin or diazinon
along the foundation will cut foraging activity, but does not guarantee
that the ants will not return. A better choice is a granular ant bait
sprinkled in a 8-12" area on the soil along the foundation. Combat®, which
is available in most retail stores, as well as the professional ant baits
Maxforce® and Advance® are commonly used for ants, including carpenter
Granular baits are not the same as the granular insecticides (such as
Dursban or diazinon) that are often used for controlling lawn pests. Read
the product labels carefully to be sure that you buy the right product.
Big Note: Any use of insecticide must always be carried out with the
utmost caution...You MUST read the label and do what it says...Also
be aware that spraying insecticide can kill none target species...And
don't forget to wear a mask..!
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