Homesellers and real estate agents who attempt to make properties more attractive by planting flowering plants and spreading around mulch may be attracting more than just buyers, according to an expert in insects.

"Homes with lush landscaping are a prime habitat for ants," says Stoy Hedges, an entomologist and author of "Field Guide For The Management of Structure-Infesting Ants." "Thick layers of mulch and heavy ground covers retain the moisture ants need to survive.

"Landscape plants, such as roses, fruit trees and many shrubs, provide a food source for ants."

Hedges heads the research department at Memphis-based Terminix Inc., where his primary study is the 40 species of ants that routinely invade homes, as well as the 500 or so other kinds typically found in North America.

With the exception of a few species -- most notably fire ants and carpenter ants -- he says they largely are more nuisance than serious problem. But they also are pervasive and hard to get rid of.

"If a homebuyer walks through a house and sees an ant, odds are very good its not just one ant," Hedges said. "Somewhere nearby there is probably a colony -- and its could range anywhere from a few hundred to tens of thousands."

While ridding a property of ants is nearly impossible and not necessarily even advisable -- "ants do more to turn the soil and aerate the soil than any other insect, and they help control a number of other insects" -- there are a few things homesellers can do to keep them at bay.

• Trim tree and shrub branches away from the buildings.
• Keep heavy ground cover out of landscape beds that are next to the house.
• Rid the yard of potential nesting sites for ants including old landscape timbers, stumps and dead limbs.
• Avoid the use of stones and landscape timbers near the house foundation.
• Keep mulch at least 12 inches from the foundation, and,
• Of course, seal cracks in outside walls and foundations and install tight-fitting screens on vents and windows.

Even with such precautions, Hedges believes the only real way to keep the pests out of the house is with routine professional pest control.

"Usually there is a colony outside somewhere, usually in wet wood like a timber or tree trunk," he said. "But they may set up as many as 20 satellite colonies."

Once a scouting female (all ants seen outside the colony are sterile females) finds a source of food and water, she lays a chemical trail back to either the colony or the satellite. Ants have been known to forage as much as 700 feet away from the colony.

Or, the nest could be as close as a curtain rod, wall clock or any other enclosed area that is not routinely cleaned.

The most troublesome ants are fire ants (stretching from Tennessee south and west to Central Texas, with some colonies now being found in Southern California) and carpenter ants (from New England back to the Midwest).

Fire ants attack anything, including people, that invade their territory. Attacks are rarely fatal to humans. Carpenter ants can damage homes, but not usually as much as termites.

And, says Hedges, although unsightly, ants usually do not carry the kind of bacteria and diseases known to be borne by cockroaches and other pests.

Published: May 26, 1999

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