DYER COUNTY, TENN., DISCOVERS INFESTATION OF RED FIRE ANTS

DYERSBURG, Tenn. -- A colony of the most aggressive and dangerous ants in the South was discovered here last month, more than 80 miles from what was thought to be their northern limit.

The colony of red fire ants was found when workers from Dyersburg Fabrics, inspecting equipment at the firm's plant site, noticed "a clump of dirt several inches high with ants on it."

"We were out there inspecting a piece of equipment and barely touched the mound," company engineer Richie Manning said, "and they just swarmed out and covered the mound in seconds."

Dyer County Extension Agent Larry Skinner, skeptical the insects were red fire ants, scooped some into a jar and sent the sample to the University of Tennessee Department of Agriculture for positive identification.

"It's surprising," University of Tennessee entomologist Dr. Frank Hale identified the ants. "We didn't think the red fire ant would come as far as northern Tennessee."

Hale's finding was confirmed by the U.S. Department of Agriculture's Animal and Plant Health Inspection Service in Atlanta.

The insect is endemic to the South, extending into Tennessee's southern border counties with Mississippi and Alabama. The species arrived in the United States in 1930, when it was discovered in the Mobile, Ala., area. In the years since, the ants, originally from South America, have moved steadily north.

The Dyersburg colony is thought to have been brought in in plants and shrubs used to landscape the factory, which was built in 1993. The colony is estimated to be at least a year old, which means the colony has already survived one winter.

"Our last few winters have been pretty mild," said Hale. "That's when they should have been killed out by the low temperatures. A cold winter might still do them in."

Plant nurseries south of U.S. Highway 64 from Pulaski, in south-central Tennessee, to Memphis are under a permanent quarantine for the red fire ants, to keep them from moving any deeper into the state.

What makes the ants so dangerous is their aggressive behavior, said Hale. Whenever one ant is disturbed, it releases a chemical alarm that instantly triggers other ants to follow. The result is an army of red fire ants erupting from a mound to defend the colony.

"When one gets smashed," said Hale, "they all get agitated. If you touch their mound with a stick, they just come pouring out."

Harold McClary, a state plant inspector, was stung while getting samples.

"It's not as bad as a wasp sting, but you know when they get you," he said. "The trouble with these ants is that in no time they'll get all over you and sting you hundreds of times. I just got careless."

Red fire ants do not bite, said Hale; instead, they use a stinger at the end of their body.

Young children and older adults are most at risk if a red fire ant mound is disturbed, said Hale, because of the ants' quick movement. People allergic to red fire ant stings are also in danger because the ants' venom is more toxic than in other ant species.

A red fire ant sting initially causes sharp pain. Hours later, a white raised pustule appears on the skin.

Skinner said red fire ants are found most commonly in pastures, with their telltale mounds several inches high.

"Most of the ants we have here are common ones, like carpenter ants," he said. "They don't have as extensive of a mound system as the red fire ant does. People should be aware of them, though."

The colony, which has grown to two mounds several feet apart, will be destroyed next week by injecting 10 gallons of water with 2 ounces of an insecticide into the mound, said McClary.

If the ants have migrated beyond the mound, a growth regulating chemical will be spread around to bait the insects. The chemical will make any remaining fire ants sterile, he said.