Drought-affected farmers forced to buy hay from out of state can take steps to avoid introducing red imported fire ants totheir farms.

The red imported fire ant (RIFA) is a major pest in much of the southern U.S. In Texas alone, its estimated economic impact totals morethan a billion dollars annually.

RIFA can spread to new locations by stowing away in bales of hay, nursery stock and other products that contain or have been in contact with soil, said Richard Houseman, University of Missouri Extension state entomologist and associate professor at the MU College of Agriculture, Food and Natural Resources.

“The threat of red imported fire ants becoming established inMissouri is a serious risk that would have long-term economic andecological impacts on both rural and urban populations,” Houseman said.

The ants can inflict damage on livestock, crops, farm equipment andeven roads and bridges. They respond aggressively when threatened, biting and repeatedly stinging victims with a painful alkaloid venom.

To avoid all that, farmers should follow some important guidelines:

  • If you have to buy your hay from RIFA-infested areas, make sure ithas been certified RIFA-free by either the USDA or an appropriate regulatory official in the state of origin.
  • Visually inspect hay on arrival, even if it has been certified, Houseman said. To draw out any ants that may be lurking within, place some attractive food on each bale, such as a dab of peanut butter, a piece of hot dog or a scrap of cardboard soaked in peanut oil. Thatshould attract RIFAs within the hour.

“If you find ants in a shipment of hay, collect several specimens and place them in alcohol,” he said. Once you have specimens, immediately notify your local MU Extension center, the Missouri Department of Agriculture or USDA’s Animal and Plant Health Inspection Service (APHIS).

  • Don’t store baled hay directly on the ground. Raise bales severalinches by placing them on pallets or old tires. This will discourageants from migrating into or out of the nearby soil.

Eliminating RIFA colonies is a two-step process, Houseman said.

The first step is to apply bait specifically formulated for RIFA to the area surrounding the colony. RIFA baits, which usually consist ofprocessed corn grits coated with soybean oil that contains insecticide, can be applied around colonies using a broadcast spreader. These baitscontain low amounts of slow-acting toxin, so effective control might take weeks or even months.

Because red imported fire ants are not established in Missouri, RIFA-specific baits may not be readily available over the counter, sofarmers might need to order bait onlineor travel to an area withestablished RIFA populations.

Houseman notes that not all RIFA baits are registered for use inMissouri. Those that are include Extinguish, Extinguish Plus, Esteem andAmdro Pro.

The second step is to apply a contact insecticide directly to thecolony, he said. This should eliminate the main portion of the colonywithin a few hours. Contact insecticides include acephate, carbaryl, pyrethrinsand prryethroids and are available over the counter under variousbrand names.

Houseman cautions there are no contactherbicides labeled for direct application to hay. He recommends eliminating populations in bales byplacing 1/3 cup of bait next to infested bale.

APHIS has also released a two-page advisory for producers, sellers and buyers of baled hay, which can be downloadedhere.

General information about identifying and controlling fire ants is availablehere.