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Anyone who
has trees on their property has probably seen carpenter ants in their home
at one time or another. Carpenter ants are typically large ants, although
the size of the workers can vary in a single colony. Finding one or two
carpenter ants a week in a home is not necessarily a sign of an infestation.
Foraging ants roam far and wide looking for food and an occasional ant
trapped in a sink or bathtub is quite common. If there are trees close to
the home, ants can be blown off the trees onto the roof. They may end up
trapped within the home during their journey back to the nest.
The first thing to remember about carpenter ants is that they do not eat
wood! They get their name from their habit of hollowing out wood in order to
make a suitable nesting site. In addition to wood, carpenter ants will nest
in synthetic foam and rigid board insulation (RBI) panels. A good indication
of a carpenter ant infestation within a home is the presence of numerous
foraging ants, especially in the kitchen or bathroom. Water attracts
carpenter ants as much as food and moist wood around leaky pipes and drains
provides an ideal environment for nesting ants. Another sign of an
infestation is the presence of large winged ants in late spring and early
summer.
Most carpenter ant colonies start outdoors in a tree cavity. After a few
years, the colony grows and expands its foraging territory. If suitable
conditions are found within a nearby home, satellite colonies may become
established in voids, moist wood, or foam panels in the home. These
satellite colonies will contain workers, older larvae, pupae, and when
conditions are right, some winged reproductive. Once a satellite colony has
become established within a structure, the potential for finding additional
satellite colonies increases dramatically.
Control of a carpenter
ant infestation must start with a complete and thorough inspection. Useful
inspection tools include a flashlight, a thin bladed screwdriver for probing
the wood, a stethoscope, and a moisture meter for locating high moisture
areas. Since carpenter ants are most active at night, the best time to
perform an inspection is after dusk. However, this can be impractical for
residential accounts. Two prime considerations should be kept in mind while
performing an inspection; find the voids and follow the water. Although
carpenter ants are usually found in wood, any dark, damp cavity can provide
a suitable nesting site. Carpenter ants make a noise like crinkling
cellophane as they move about. A stethoscope makes them much easier to hear
and locate. Tapping the suspect area excites the ants and you should be able
to hear their movement.
When carpenter ants
burrow into wood they generate sawdust or frass that can pile up beneath the
site of their activity. Carpenter ant frass looks like tiny wood shavings
and will often contain parts of dead insects. Look closely at all of the
wood directly above any frass piles for signs of an infestation. Probing the
wood with a thin bladed screwdriver can reveal hollowed out areas.
In addition to food and
a nesting site, carpenter ants require water. That's one of the reasons they
prefer to nest in damp wood. A moisture meter is a great tool for
discovering actual and potential carpenter ant nesting sites. A moisture
reading of over 20% is an indication of some type of water problem that
needs to be corrected.
TREATMENTS
Correcting water leaks from faulty plumbing and roof leaks is the most
important step for long-term carpenter ant control. Even after any leaks
have been repaired, enough moisture may remain to sustain a carpenter ant
infestation for many months. The application of a contact pesticide directly
to the colony is not the best way to control an infestation. Most contact
pesticides are highly repellent causing the ants to scatter, thus creating
the potential for additional satellite colonies to become established in
other areas of the home. In addition, contact pesticides do not impart any
long-term residual protection to the wood. After a few months, carpenter
ants may return to the site of their original infestation.
A better way to control a carpenter ant infestation is to treat the
infested area and those areas subject to infestations with a borate such as
Shell-Guard and Armor-Guard. Both Armor-Guard and Shell-Guard are effective
pesticides for eliminating and preventing carpenter ant infestations. We
recommend using Shell-Guard for treating active infestations because the
glycol components aid the penetration of the borate into the wood where the
carpenter ants are nesting. This results in quicker control. Areas that have
been treated with Shell-Guard will also be protected against future
infestations. Armor-Guard is best used as a dust in wall voids and other
areas as preventative measure. Finally, apply an appropriately labeled bait
around the perimeter of the home. This will decrease the carpenter ant
population in the area and reduce the pressure on the home.
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