How climate change is fueling Virginia’s fire ant invasion

Fire ants, shown here, resemble garden-variety ants, making them difficult to spot, experts say. (U.S. Department of Agriculture)

By Jeremy Cox on March 18, 2020, Bay Journal
 
In Virginia, climate change is about as welcome as ants at a picnic. But across a portion of the state’s southeast, ants are part of the problem.

Since 1960, the annual average temperature in Virginia Beach, the region’s most populated city, has risen about 3 degrees, according to the National Oceanic and Atmospheric Administration. That warming trend has opened the door for fire ants — normally living in more southerly areas — to gain a stubborn foothold in the state, Virginia agricultural officials say.
And it’s growing larger.

“It’s an unfortunate side effect” of climate change, said Eric Day, a Virginia Tech extension entomologist. “We have warmer winters and warmer summers, so it certainly makes for good conditions for fire ants.”

The Virginia Department of Agriculture and Consumer Services announced in December that it was expanding its fire ant quarantine to five new counties and two separate cities. With the addition, the quarantine now spans one or two counties deep along the North Carolina border from just west of Interstate 95 east to the Atlantic Ocean, an area nearly the size of Connecticut.


The quarantine applies to both the black and red fire ant varieties, but the red is more commonly seen in Virginia, officials say. Both damage crops and deliver a nasty sting.

Since their accidental transmittal from South America to the United States in the 1930s, red fire ants have spread across most of the Southeast from the marshy tip of Florida to the windswept plains of Oklahoma.

When the first fire ant infestation was discovered in Virginia in 1989, agricultural officials blamed the interstate trade of plants and sod. They grew so widespread that by 2009 the state announced its first quarantine in the Hampton Roads region.

It has become clear with their continued spread westward along the state’s southern border in recent years that colonies are now marching up from the South on their own, Day said. That shift points for the first time away from humans as a cause for their proliferation in the state and toward a new climate reality, he added.

Fire ants resemble garden-variety ants, making them difficult to spot, experts say. Tell-tale signs of their presence are their mounds, which can reach up to 2 feet high and damage farm equipment. The ants themselves prey on corn, soybeans and other crops, causing further headaches for farmers.

Their sting, though, may be their defining attribute. Anyone who unwittingly wanders into a nest typically emerges with a foot or leg stippled with burning welts that turn into itchy, white pimples that last for days. In extremely rare cases, the victim can suffer deadly anaphylactic shock.

Christopher Brown, who works in purchasing and product development for the Lancaster Farms plant nursery in Suffolk, knows the sensation all too well. “It’s not like getting stung by a bee where it’s one sting and that’s it,” he said. “When you get bitten by a fire ant, you’re going to get bit five to 10 times depending on how long it takes you to realize you stepped on a fire ant mound.”

Suffolk was one of the first areas to be quarantined in 2009. The designation prohibits transporting anything that can carry fire ants out of the area unless it is certified as ant-free. Regulated items include gardening soil, plants, sod, used farm equipment and freshly cut timber.

At Lancaster Farms, workers blend an insecticide called Talstar into their pine bark potting material to kill any ants that may be there, Brown said. It takes a few cents’ worth of the chemical to treat each pot, he estimated; a 15-gallon pot includes about 10-cents’ worth. That expense adds up quickly because the nursery churns out hundreds of thousands of plants each year.  “It’s a cost of business,” Brown said.

Fire ants are at the vanguard of an army of pests expected to trudge northward as fossil fuel emissions continue heat up the planet during this century. A U.S. Department of Agriculture-sponsored study in 2005 predicted that warming temperatures will increase the “habitable area” for red fire ants by 21% by the end of this century, pushing their upper boundary about 80 miles northward. By some time between 2080–89, fire ants could occupy a swath of Virginia as far west as Roanoke and stretching along a line bearing northeast toward the District of Columbia, according to the study. Maryland and Delaware can expect to see their first invasions by that time as well, it says.

Fire ants in VA

• 2009 quarantine areas: Counties of James City and York; cities of Chesapeake, Hampton, Newport News, Norfolk, Poquoson, Portsmouth, Suffolk, Virginia Beach, Williamsburg
• 2019 quarantine areas: in addition to those listed in 2009, the counties of Brunswick, Isle of Wight, Greensville, Mecklenburg, Southampton; cities of Emporia and Franklin

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