Hybrid fire ants , well established in East Tennessee and parts of Kentucky and North Carolina, are now infiltrating Southwest Virginia.

Imported red and black fire ants first appeared in Virginia in the early 2000s near the North Carolina border. Virginia’s increasingly warmer climate, including milder winters and hotter summers, has created more favorable conditions for fire ants.

As temperatures rise and winters become less severe, the aggressive ants are expanding their range farther north into the state.

“It’s just one more nuisance,” said Amy Byington , a Virginia Cooperative Extension agent who leads efforts in Lee County to report and treat the issue. “I get calls every week from landowners who are discovering new ant mounds on their property.”

Byington partners with the Virginia Department of Agriculture and Consumer Services to locate and treat the mounds.

“One of my producers recently reached out and reported they had found six fire ant mounds on their farm,” she said. “The VDACS inspector later ended up counting 58.”

So far, Lee County is the only county in Virginia with a presence of hybrid fire ants, although this is expected to change as ants gradually extend their territory north and east.

Hybrid fire ants are extremely aggressive and tend to swarm when their mound has been disturbed. Pheromones released by the ants quickly alert colony members to the threat, leading to a mass attack and many stings by the defending ants.

“People need to be educated on these ants so they can prepare,” said Byington. “They are dangerous for populations not used to dealing with them and who initially treat them like normal ants.”

Hybrid fire ants have developed ‘superpower’

Hybridized fire ants are the result of interbreeding between the red imported fire ant and the black imported fire ant resulting in a more resilient species.

Scotty Yang , assistant professor in the Virginia Tech Department of Entomology within the College of Agriculture and Life Sciences, said hybrid fire ants have developed a “superpower” that allows them to thrive in in Virginia.

“When two different species interbreed, they can ‘borrow’ genes from one another,” he said. “If those borrowed genes happen to be useful – say, for surviving cold winters – they may stick around and give the hybrid a leg up in adapting to its environment.”

Hybrid fire ant quarantines

Hybrid fire ants may be transported and spread through bales of hay, vehicles, trailers, farm equipment or firewood.

VDACS and the U.S. Department of Agriculture have set up state and federal fire ant quarantines in southeastern Virginia, where the red imported fire ant is prevalent, but the quarantine hasn’t been expanded to Lee County or any areas in Southwest Virginia.

“They’re advancing much faster than anticipated,” said Yang. “While it’s hard to say exactly when fire ants will establish themselves permanently in the New River Valley or Roanoke, given this rapid movement, it could happen as soon as the next few years.”

If you suspect hybrid fire ants on your property, contact your local Cooperative Extension office for free testing or call VDACS at (804) 786- 3515.