Two kinds of ants are surprisingly troublesome and costly invaders of our homes, yards, and parks.
Fire ants infiltrate traffic signals, electrical switch and telephone boxes, and air conditioners, creating a need for costly replacements, while pharaoh ants are more likely to migrate into warm buildings. Fire ants alone have caused over half a billion dollars in damage costs and control efforts since they entered the United States at the turn of the century.
Now, after studying the ants' behavior, Agricultural Research Service chemist Robert Vander Meer has found a nontoxic way to stop their invasive habits. He discovered and patented several noninsecticidal ant repellents--the first of their kind.
Vander Meer is in ARS' Center for Medical, Agricultural, and Veterinary Entomology's Imported Fire Ant and Household Insects Research Unit at Gainesville, Florida.
The repellents are volatile chemicals with a high vapor pressure that evaporate rapidly into the air. Laboratory tests show that combining the repellents with a slow-release material, such as powdered corn starch, will extend the repellent's active life in the field up to a year.
"The repellents are ideal alternatives to insecticides, especially in state or national parks and other areas where their use is limited--or even prohibited--because of possible human contact," says Vander Meer. "The repellents are a way to keep the ants at bay, so to speak. When applied, they inhibit foraging and keep ants underground."
Fire ants infest an estimated 278 million acres in 11 southern states and Puerto Rico. Known for their burning sting, they bother about 30 percent of the population within infested areas each year.
Pharaoh ants, on the other hand, are urban dwellers and cause most trouble indoors. They are a worldwide pest, occurring in temperate and tropical climates. During cold winter months, in northern states, the pharaoh ants take up residence in buildings and homes.
Vander Meer says the next appropriate step would be to test the repellents' effects on other ant species. "We are currently studying their effects on the Argentine ant, which is also a pest worldwide," he says.--By Tara Weaver, Agricultural Research Service Information Staff.
Robert K. Vander Meer is in the USDA-ARS Imported Fire Ant and Household Insects Research Unit, 1600 SW 23rd Dr., Gainesville, FL 32604; phone (352) 374-5918, fax (352) 374-5818.
"No Ants Allowed!" was published in the July 1998 issue of Agricultural Research magazine. Click here to see this issue's table of contents.