window and door casings where
This slender ant is about 1/8 inch long; it has
rain water hits, or
only one node; it is light to dark brown with a silky
older buildings and historical buildings
shine; the head is triangular or heart shaped. As it's
that haven't been kept up. [Fungus or
name indicates, it was introduced from South America.
Its habits in its primary continuous range -- from the
rot problems are very likely more
important here than ant damage.]
Gulf Coast to southern California -- is different than in
isolated urban centers in other parts of the United
In the primary range, these ant populations are
Remove and replace damaged wood.
intense. They constantly infest and reinfest structures
Change grade and redirect downspouts
and agricultural land (e.g. citrus orchards and cane
that pitch water toward structural wood.
fields). Argentine ant colonies are often large and
Clean or replace gutters.
compatible: Workers and queens of different colonies
Trim overhanging tree limbs that keep
are not antagonistic toward each other; foragers
wood from drying.
maintain vigorous trails that often coalesce with those
Move logs, stumps, leaves and grass
of other colonies. Argentine ants tend honeydew-
clippings away from structures.
producing insects, protect them from their predators,
and are known to move aphids to other plants where
they begin new infestations. They will not tolerate
Habitat alterations will usually stop the problem.
other species of insects, especially other species of
Use contact sprays if needed.
ants, within their foraging range. Argentine ants seek
sweets: outdoors -- honeydew from insects and plant
nectar; indoors -- juices, sugar, and syrups.
Susceptible structures, especially buildings with
Populations have been introduced in urban areas
historical significance should always be periodically
outside the primary range with the transfer of plants
monitored. Detailed records concerning pest
and household goods; these infestations are smaller
infestations, treatments and repairs should be kept on
and local. This secondary distribution includes many
southern cities where exterminations and
reintroductions proceed on a case-by-case basis. Other
Other small to medium-sized ants are the Small
Honey Ant (Prenolepis imparis), Corn Field ants
more northerly cities (where the Argentine ant is
Lasius species), and the Velvety Tree ant (Liometopum
established but not a primary problem ant) include St.
Louis, Chicago, Baltimore and probably other areas
where it has not been recognized. They usually do not
overwinter outside in these areas.
(around 1/8 inch long)
In the Primary distribution area where Argentine
ants commonly infest the majority of structures, make
In this group of ants the workers are larger than
every effort to locate nests outside near the infested
the tiny ants, but well under 1/4 inch in length.
Several interesting structure-infesting ants are in this
Inspect soil area next to foundations
especially moist soil.
Survey for colonies of honeydew-
THE ARGENTINE ANT
Inspect shrub stems and under plant
Follow ant trails and identify nests,
food, and active entry points into
Inspect nearby manholes and steamline
Inside populations tend to be relatively small, less
active, and can be eliminated temporarily. Locate the
Module One, Chapter 3, Pg 8