Fire ants were first detected in Virginia in 1989 at a golf course in Hampton. They stayed in Southeast Virginia until 2017.
But since then, the invasive species has been spreading westward at a fairly rapid pace.
Red imported fire ants are a small insect, about an eighth of an inch long or less, but they “pack a powerful punch,” said Eric Day, a Virginia Tech entomologist, or a scientist who studies insects.
Named because their sting creates a burning pain, the red and black mountain-building ants are a threat to agriculture, livestock and people.
In 2017, fire ants were detected in Brunswick, Mecklenburg and Halifax counties in Southside, said Day.
But they didn’t stop there. Fire ants have been spotted in Danville, Bristol and even in the state’s westernmost tip. A quarantine that started in Tidewater in 2009 has been expanded several times and now stretches into Southside.
This expansion, after about three decades of staying put, is because of climate change, Day said. And as long as global warming continues, the spread of fire ants is likely to continue too, he said.
“For the longest time, [fire ants] were only expected to be in far southeast Virginia,” he said. “Once you go beyond that Tidewater area, the winter temperatures were thought to be too cold for fire ants to survive or build up in numbers, and the summers weren’t hot enough.”
But now, with warmer winters and summers, places in Southside Virginia have become very suitable for fire ants to live, he said. They’ve also spread up from North Carolina, Day said, which borders these Southside counties.
And now, Southwest counties are at risk, too.
“We’ve recently had a detection in Lee County, which was initially off our radar screen, but it turns out a lot of the Tennessee counties just across the state line are infested with fire ants,” Day said. “That was a big wake-up call for us.”
The fire ants detected in Lee County were hybridized fire ants, which are different from the red imported fire ants that the rest of Virginia is familiar with. The hybridized ants are a bit more suited to cooler climates, he said.
In 2009, a fire ant quarantine was imposed in much of the Tidewater area. Because the ants began to spread, the quarantine area was updated in 2019 and again in 2022, now encompassing 12 counties and 11 independent cities in the southeast and central parts of Virginia.
The 2022 update includes five Southside counties: Sussex, Dinwiddie, Lunenburg, Charlotte and Halifax.
The goal of the quarantine is not to eradicate fire ants, only contain them, said David Gianino, plant industry services program manager for the Virginia Department of Agriculture and Consumer Services.
“The purpose of the quarantine is to reduce the artificial movement or human-assisted movement of the imported fire ant and to prevent it from leaving areas where we know that it’s infested into areas where we know that it’s not infested,” Gianino said.
Fire ants can spread if they are on articles like nursery stock or sod that are being transported from one area to another. They can also spread on their own, but human intervention drastically increases the speed and volume of the spread.
The quarantine “prevents the movement of those articles from leaving a quarantine area or a generally infested area, unless those articles have basically met a couple of different qualifiers,” Gianino said.
One qualifier would be receiving a specific treatment to kill fire ants, and documenting that the products being moved have been treated. Another would be inspecting all products being moved to ensure that they’re free of fire ants.
Red imported fire ants at a glance
Size: ⅛ of an inch long, or less
Scientific name: Solenopsis invicta
Color: red, with a black or brown posterior
Area of origin: South America
Habitat: wide variety, including rainforests, deserts, grasslands, alongside roads and buildings and in electrical equipment
Venomous? yes
“Let’s say you’re a business that routinely goes in and out of a quarantine area and you drive a truck, but it parks in a gravel parking lot that has fire ant mounds,” Gianino said. “You’d have to inspect that vehicle every single day before leaving the quarantine area.”
If fire ants are found during an inspection, they need to be brushed or washed off, along with any soil or other material that might help transport them.
A quarantine can be state or federally imposed, though the Virginia and U.S. departments of agriculture have harmonized their quarantines, Gianino said.
“When the state expands their quarantine, the USDA tends to follow suit to match the state quarantine,” he said.
The quarantine is extended to an area when it is deemed “generally infested,” or when mounds can be found ubiquitously throughout the locality, Gianino said.
But just because an area isn’t under quarantine doesn’t mean that fire ants aren’t a problem there. Fire ants have been spotted in non-quarantine areas of the state, like Bristol and Danville, Day said.
Mounds in Danville were discovered last summer in several places in the city and in Angler’s Park, said Corey Riedel, the city’s agriculture extension agent for Virginia Cooperative Extension.
“They’re here in Danville, we’re just not under the quarantine yet,” Riedel said. “But I’m assuming the quarantine will extend here either this year or next year.”
Fire ants are classified as an agricultural pest, Gianino said, but they also pose risks to livestock and young children, and they can even harm soil quality. The ants are very aggressive and territorial, he said.
“When their mound is messed with or their area is under threat, they will swarm out in dozens or even hundreds,” Gianino said. “They’ll climb onto whatever they perceive as a threat, and they almost have a coordinated sting. As a group, they’ll get onto your hand or foot or wherever and they’ll coordinate their stings really quickly together.”
The stings have venom in them, he said, causing small pustules that can burst and get infected if not treated.
“Those infections can impact not only young children, but young agricultural animals, especially grazing animals like sheep and cows,” Gianino said.
If calves get stung right after birth, that can result in irritation at best and blindness or even death, Day said.
There’s an educational curve to combat, Day said, because not everyone is aware of these threats or of the quarantine.
The USDA website has information about the imported red fire ant, and the VDACS website has information about the Virginia quarantine. Virginia Cooperative Extension has a fire ant fact sheet with a description of the insect.
“Just be careful if you’re moving loose soil. Even potted plants can possibly move fire ants,” Day said. “The main thing is always certainly going to be human safety. If you get stung, monitor your reaction. If you have a severe reaction, see a medical professional.”
And if you spot fire ants, or what you think might be fire ants, call your local extension agent or or the Department of Agriculture and Consumer Services, Riedel said. Virginia Cooperative Extension has agents in every city and county in the state.
“If you’ve talked to VDACS and you’re outside of the quarantine area, they will actually come and take care of the mounds for you, so you don’t have to worry about doing it yourself,” Riedel said. “If you are in the quarantine area, unfortunately, then you’re going to have to do your own, but they can tell you how.”
Gianino said it’s difficult to assess how successful the quarantine has been. VDACS is used to regulating agricultural entities, like farmers, nursery stock growers and people moving plants around.
“But when we put in these quarantines, what we realized is there are extra groups, extra entities that we did not think about before,” Gianino said. Organizations moving things like firewood or even solar panel equipment can spread fire ants, and those don’t typically fall under VDACS’ purview.
So enforcing the quarantine has involved a lot of outreach, Gianino said.
“We’ve had to connect with different associations and groups, and anytime we can get the message out about how to comply with the regulations, it’s really important to do so,” he said.
But despite the difficulties with outreach and education about the quarantine, things would likely be worse if there were no regulations, he said.
“If we didn’t have a quarantine at all, what would the spread be then?” Gianino said.
Fire ants have been in the United States for many decades, and people have had to learn to live with them, Day said.
“Unfortunately, they’re here to stay,” he said. “They’ve adapted pretty well to North American conditions.”
Still, Day said he’s optimistic that people will continue to learn about this issue and be aware of it. Riedel agreed that Virginia has the potential to keep its fire ant issue manageable, but it likely won’t ever go away.
“It’s mostly just about educating folks, especially those that are working with sod or at a nursery,” Riedel said. “I’m optimistic that we can keep things under control, but they’re going to keep spreading. Looking at the history of everything, it doesn’t really look like we can stop it. We’re just going to have to deal with the problem and slow it down.”