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Red imported fire ants attack a gloved hand that disturbed a mound recently in the Dallas area. (Texas AgriLife Extension Service photo by Mike Jackson.)

By: Mike Jackson, 972-952-9232  
Contact(s): Kim Schofield, 972-952-9221, k-schofield@tamu.edu 

DALLAS - When people think of Memorial Day they’re often reminded of picnics, cookouts and activities in the park.

But this year, as the unofficial first day of summer approaches, they might also think about applying pesticides for red imported fire ants, said an expert with the Texas AgriLife Extension Service.

"Fire ants are most active in the summer, from May through September, so late spring is a good time to apply baits or other pesticides to infested areas," said Kim Schofield, an AgriLife Extension program specialist in Dallas.

Ants have been known to crash picnics, but fire ants aren’t an average pest, Schofield said.

"Imported fire ant workers bite with mandibles or jaws and sting aggressively and repeatedly, since they have a smooth stinger," she said. "After the first sting, it can rotate its stinger and sting again, leaving a circular pattern of stings."

Fire ant stings should be treated like those from other insects, by keeping the wound clean to avoid infection, Schofield said. After several days, the wound will appear as a pustule that takes about 10-14 days to heal, she said. For more information about stings, visit http://www.extension.org/pages/Fire_Ant_Stings .

Pesticides can help control fire ants, she said, which also helps beneficial native ants return to the landscape. Pesticide instructions should be followed carefully, she advised.

Fire-ant baits, drenches, dusts and contact granular insecticides may be applied to control fire ants, Schofield said, who recommended treating individual fire-ant mounds directly if there are fewer than five mounds on a quarter-acre or fewer than 20 on an acre.

Where there are more mounds, fire-ant bait or contact insecticide should be broadcasted over the entire infested area, she said.

"Before broadcasting the fire-ant bait, foraging activity should be assessed, by placing a potato chip or hot dog next to the mound," Schofield said. "If fire ants find the chip or hot dog within twenty minutes, then it is a suitable time to broadcast the bait."

For more information, please visit the fire ant webpage at http://fireant.tamu.edu .

While pesticide applications can be effective on individual properties, homeowners and other property owners would have more success if entire neighborhoods were treated for the pests at the same time, Schofield said.

"You have a better chance of controlling them by treating large areas such as an entire neighborhood at one time with a fire-ant bait, so they would all be killed instead of returning from your neighbor’s untreated yard," she said.

Red imported fire ants are native to South America and arrived in the U.S. in the 1930s aboard ships in Mobile, Ala., according to the Texas Imported Fire Ant Research and Management Project. They spread to southern states, arriving in Texas in the 1950s.

In Texas, they cost about $1.2 billion annually in agricultural losses, ecological damage and pesticide expenses, according to Texas A&M’s fire ant economicss website, http://fireantecon.tamu.edu . Their sting makes them dangerous to humans, livestock, pets and wildlife.