Mild Winter Means Greater Fire Ant Threat (225)

KNOXVILLE, Tenn. — Pesky fire ants may march into Tennessee this summer because of the state’s mild winter, a University of Tennessee entomologist said Monday.

 Dr. Karen Vail said cold temperatures usually slow migration of the ants, which came from Brazil on plants imported to Mobile, Ala., and have spread north.

 Mild temperatures this winter, however, mean larger fire ant populations and a greater likelihood they will move further north, she said.

 “The cold temperatures slow it down around the state’s southern border, but they may creep slowly northward this summer,” Vail said.

 The ants build large mounds which damage roads and crops, Vail said. They attack aggressively by the thousands if disturbed, she said.

Vail said entomologists had thought fire ants could not live where temperatures dip to 10 degrees or below at least once a year for consecutive years.

 It was believed that this “10-degree line” just north of Tennessee’s southern border would stop the ants from moving upstate, she said.

 New studies, however, show that fire ants can withstand such temperatures, Vail said.

 “There is evidence that they may be adapting, and with the mild winter, I think the populations that are present in Tennessee are very healthy,” Vail said.

“That means greater numbers will reproduce, more offspring can fly north in mating flights, and more will spread through movement of sod, plants and other shipments.”

 —

 Contact: Dr.Karen Vail (423-974-7138)