The common names moisture ant and turf ant come from these ants’ habit of nesting and foraging in moist soil, rotting wood and turfgrass/lawns. Perhaps the best-known species of moisture ant is the cornfield ant, Lasius alienus, so-named because of its activity and nests in the vicinity of cornfields. The Genus Lasius is well-represented throughout North America.
APPEARANCE AND BEHAVIOR
Moisture ant workers measure about 1/8 inch long and can be yellow, light brown, dark brown or nearly black in color. The winged reproductives measure 1/4 –3/8 inches long (not including wings) and are glossy brown to black in color. Although no stinger is present, these ants will bite and secrete pungent-smelling formic acid onto the persons or animals harming them or disturbing the colony.
Colony size typically ranges from a few hundred to several hundred individuals. Favored nesting sites include rotting logs and landscaping timbers (and the soil beneath), decaying stumps, crop land and detritus-covered soil of fencerows and woodland settings. Swarming occurs in late summer through early autumn in natural settings.
Moisture ants may arouse the concern of persons who notice the fall-winter swarms in landscaping, basements and crawl spaces. Moisture ants tend to import soil into sites in buildings chosen for nesting, including the voids of concrete block, insulated sill plates and floor drain tiles. Similarly, nests may be located beneath slab foundations and in soil-floor crawl spaces. In such cases, the worker ants may be observed to forage indoors and the alates will aggregate around lights and windows.
MOISTURE ANT CONTROL AND PREVENTION
Moisture ants that occasionally enter or swarm in buildings can be removed with a vacuum cleaner fitted with a hose attachment. Foraging by these ants in lawns and planting beds can be discouraged by controlling dandelions and other weeds. Trees that are infested with honeydew-producing insects can be made less attractive to foraging ants by periodically spraying the trunks with a 1 or 2% detergent solution or appropriately-labeled water-based garden insecticide in a 2 to 3 foot high band pattern at the base.
PROFESSIONAL PEST CONTROL
When you call us for moisture ant treatment, a Plunkett’s pest control technician will come by and apply a foundation perimeter treatment with residual liquid insecticide to discourage structural invasion. Spot treatments using a residual liquid insecticide will be made to nests located in the sill plate, crawl space and landscape.