Keep the granule bait close, and the Benadryl closer.
It’s the sting that keeps on giving … and hurts like hellfire. A venomous, unbarbed stinger, capable of multiple injections, produces manic bucking and slapping in its victims. To the uninitiated, the description may seem an exaggeration, but the searing burn of swarming fire ants testifies to the contrary.
Invasive fire ants, six-legged devils barely an eighth of an inch long, are a scourge to farming and livestock production. Arriving on American shores roughly 80 years back and facing no natural enemies, they spread across the entire Southeast and then west to California. Poisoned stings are a genuine nuisance (and can even produce anaphylactic shock), but their true impact is a multi-billion dollar slam to the U.S. economy each year, particularly the agriculture industry. The cumulative financial damage wrought by fire ants continues to climb toward shocking totals. In 2006, Texas A&M University research estimated fire ant damage to the overall U.S. economy at $5.65 billion per year.
The Midwest has been watching and waiting for several years, hopeful that fire ants remain an affliction confined to the warm, bottom tier of the U.S. Weather permitting, that may be precisely what happens, according to Sanford Porter, a research entomologist with USDA-ARS in Gainesville, Fla. “Fire ants thrive in heat, but die when it freezes.”
Damaging Machinery, Equipment and Crops
Fire ants are notorious for damaging agricultural vehicles and equipment of all sorts. “They’ll haul in dirt and build nests inside the warmth of any type of electrical equipment,” Porter explains. “Fire ants get fried when they hit switches and release pheromones causing more ants to swarm. It’s a mess of broken switches, dirt and ill-tempered ants.”
Fire ants also cause tremendous damage to irrigation equipment. A grower can check a pump one day and find it clean and ant-free. But the very next day, a nest pops up seemingly from nowhere and brings with it a tangle of short circuits.
Raised fire ant mounds are typically 1’ or lower, but can reach over 2’, easily capable of dulling blades or breaking equipment. “I’ve seen pastures with 200 mounds per acre, translating to millions of fire ants. As a producer, that means you’ve got to be on a constant hunt for them,” says Blake Layton, an entomologist with Mississippi State University Extension. They function as half herbivore and half scavenger carnivores, killing small livestock or wildlife, ruining pick-your-own operations, and necessitating hay bale quarantines and certification.
Fire ant damage can even extend directly to crops, according to Layton. “They sometimes damage corn, soybeans, or milo. If you don’t get a good seal on the furrow, they’ll feed on seed and take the germ out. They’ll also girdle the stem of citrus trees, access the sap and permanently damage the trees.”
As for control? Granular baits at farm scale are cheap and work well, but are fairly slow acting, taking two to six weeks to knock out a colony. Layton recommends using a Herd broadcast seeder at 1 to 1.5 lbs. per acre. “Some producers add the bait to fertilizer, but that’s a mistake,” Layton warns. “Fertilizer dries out the bait oil and the ants won’t consume the granules as well.”
Ranging from Virginia to Florida; Tennessee to Oklahoma; and Texas to California, fire ants spread roughly 5 to 20 miles per year, according to Porter. There are two species of invasive fire ants in the U.S.: black and red. “We think the blacks came in about 1915 from South America in timber shipments, followed by the reds in 1930. In South America, the two species don’t interbreed, but curiously, they do in the U.S. The northern halves of Mississippi, Alabama, and Georgia are filled with hybrid fire ants.”
Despite demanding farmer vigilance and pounding the U.S. economy for billion-dollar losses, where will their march end? “Is the Midwest safe? Right now, as long as you get ground freezing to a half foot depth, fire ants don’t do well,” Porter says. “But up the warm coasts? They could reach Delaware in the East and Seattle in the West.”