Beware of Fire Ants Hiding in Imported Hay from South

The aggressive insects have become significant pests in southern states.

Published on: Jun 17, 2009
Missouri farmers who are considering purchasing hay from parts of the southern U.S. should think twice. The imported fire ant, an aggressive, stinging insect native to South America, has infested more than 380 million acres in at least 13 states, according to the USDA's Animal and Plant Health Inspection Service. The ants can spread to new locations as stowaways in bales of hay.

"The increased trade and transport of hay into Missouri over the last few years has increased the risk of the pest being transported into the state," says Brian Deschu, APHIS domestic program coordinator in Jefferson City.

"I've been concerned about fire ants getting here since I came to Missouri in 2000," said Richard Houseman, University of Missouri Extension entomologist. Houseman studied for his doctorate at Texas A&M University, right in the heart of the "Fire Ant Belt." In some parts of the South, fire ant colonies are so widespread that residents learn to be careful where they step.

Imported fire ants were inadvertently introduced to this country about a century ago. Free of the natural predators that kept them in check in South America, imported fire ants have become a significant pest throughout much of the southern United States. The ants are reddish-brown or black in color and are 1/8- to 1/4-inch long, according to APHIS.

"Imported fire ants are a minor threat to agricultural crops, but are a bigger threat to the landscaping, nursery and sod industries," Houseman says. "They have a major impact in residential areas. They produce unsightly mounds, enter residential structures and deliver a potent sting when they are threatened or disturbed."

APHIS is enforcing a federal quarantine that regulates the transport of certain items, including baled hay that has been in direct contact with the ground, soil, grass sod and soil-moving equipment. The quarantine area includes all of Alabama, Florida, Georgia, Louisiana, Mississippi, South Carolina and Puerto Rico; large portions of Arkansas, North Carolina, Tennessee and Texas; and small parts of California, New Mexico and Oklahoma.

Houseman said southern Missouri is at risk because of its proximity to existing imported fire ant infestations and a climate congenial to imported fire ants, particularly in the Bootheel region.

Imported fire ant colonies build distinctive foot-high mounds that can damage vehicles and farm equipment. Underground colonies can undermine sidewalks, roads and bridges, inflicting extensive and costly damage, he says.

If you suspect the presence of imported fire ants, Houseman recommends contacting your local MU Extension center or MU Extension's Plant Diagnostic Clinic at 573-882-3019. See for more information.

You can find out if a particular location is under quarantine through the APHIS Web site by viewing a quarantine map or entering a ZIP code at The site contains extensive information about imported fire ants, including guidelines for producers and purchasers of baled hay.

Source: MU Cooperative Media Group