The ant invasion
Two new species of ants are invading Texas. Entomologist Dr. Bastiaan “Bart” Drees of the Texas A&M AgriLife Extension visited Orange County Commissioners Court at their regular meeting Monday, Jan. 14. Drees invited community members to join him later that evening to discuss the invasive ant species spreading across Southeast Texas and the rest of the state.
Drees addressed a full house that Monday evening at the Raymond Gould Community Center in Vidor. Residents of Vidor and surrounding cities gathered to learn what they could do to fight off the pests.
“We can’t have an ant-free environment,” Drees said. “So, we want to control the bad ones.”
Drees discussed several types of “pest” ants common in Southeast Texas.
The red imported fire ant first bites, then stings and “burns like fire.” Reactions to the venom range from a small, painful welt to death.
Drees said red imported fire ants have had a $1.2 billion impact on the Texas economy and estimated that half of that was spent on products bought to eradicate ants. He said these ants are known to cause damage to electrical wiring, potentially costing big bucks to repair. He explained that one ant could get into the wiring and get shocked, killing the ant. Other ants attempt to extricate the dead ant, causing a chain reaction. Each ant is shocked and killed, eventually creating what Drees described as “a wad of ants,” causing the electrical current to be interrupted.
One community member told Drees he had spent $10,000 on fire ant control and prevention. Drees said various methods are used to control red imported fire ants. He said the most effective approach is an integrated pest management system utilizing a combination of cultural, biological and chemical control methods. As an example of biological methods used to control the red imported fire ant population, Drees mentioned the introduction of phorid flies in Texas. Phorid flies from South America are one of several species of flies that attack ants. Phorid flies specifically attack red imported fire ants.
“It’s a brain-eating fly,” Drees said of the Phorid fly.
He explained that the fly “dive bombs” the ant, then lays an egg. After the egg hatches, the larvae migrates to the ant’s head and feeds on hemolymph, muscle tissue and nervous tissue. Eventually, the fly eats the ant’s whole brain. The ant then wanders aimlessly for the next couple of weeks, described by Drees as a “zombie ant.” Before the fly pupates, it releases an enzyme causing the ant’s head to fall off. After approximately two weeks, the fly emerges from the mouth cavity of the ant’s head.
In addition to the red imported fire ant, Drees addressed issues concerning the Texas leaf-cutter ant and two non-native ant species that are experiencing a population boom in Texas, the Rasberry crazy ant and the Argentine ant.
Leaf-cutter ants, often called “town ants,” collect rose petals, leaves and other organic materials. The ants take the matter underground and pile it up to grow an edible fungus, “like a yogurt culture,” Drees said. He said these ants could be difficult to control because they harvest foliage from a two-acre area. The “town” is built in the trees and distributing poison through the breathing-holes is not feasible. One has to find the center of the colony and be directly on top of it for poisons to work.
The Rasberry crazy ant, newly named the tawny crazy ant, was originally named after the pest control professional who discovered them, Tom Rasberry. Drees said at this time, Rasberry crazy ants have been found in 24 counties in Texas, including Jefferson and Orange counties. Orange County Pct. 4 Commissioner Jody Crump was at the presentation. He said he received a number of calls and visits from citizens complaining and worrying about ants in the area. He said he shares in the worries of those gathered regarding the increasing population of some ant species.
“I’ve got Rasberry crazy ants at my house, too,” Crump told concerned citizens.
This new, exotic pest ant is spreading every year, and few treatments are effective. The crazy ants ignore fire ant baits, so Drees suggested a three-part control method. He said the first step is to have a pest professional use a product like Termidor, also used for termites, and spread the poison one foot around the house or infested structure. The second step is to use a crack and crevice treatment like Phantom Barrier. Drees said step three is the use of products like Top Choice or Taurus around the rest of the property. Drees said these ants were found in bags of mulch sold in Bexar County near San Antonio, so that is one way humans are helping spread the ants. Drees also expressed concerns that Rasberry crazy ants could invade beehives causing the bees to abscond.
Drees said the Argentine ant is another invasive species Texans are dealing with lately. These ants are native to Argentina and Brazil. They are attracted to moisture and often nest under stones, boards, plants and rotting trees. Argentine ants bite but do not sting. Drees said pretty much all of California is a super colony of Argentine ants. He said normal poisons are ineffective. In California, ant control measures being used include liquid baits, which Drees said are only mildly effective in controlling the Argentine ant population. The AgriLife website says, “Injecting dusts or aerosols through small cracks around baseboards can treat nests inside wall voids. Argentine ant nests located outside can be drenched with a residual insecticide by using a compressed air sprayer. Colonies found living in flowerbeds, mulch, and leaf litter also can be treated in this manner, but with the compressed sprayer at low pressure. When Argentine ants become numerous and are the dominant species, perimeter treatments repel foraging ants and prevent them from re-infesting the property and invading structures. Insecticides used for these treatments should be a wetable powder or micro encapsulated formulation labeled for this type of application. If colonies cannot be located, bait insecticides can be used in stations, placed along foraging trails in numerous locations. Argentine ants are particularly attracted to sweet baits. Regular follow-up visits will determine if bait stations need to be replenished and if colonies have been eliminated.” Drees said Argentine ants are the most difficult to control with current methods.
For general ant control and prevention, Drees suggested a two-prong approach. He said using insecticides or ant poisons on mounds in conjunction with using bait across the property is the most effective way to fight the invasion of the ants. For more information regarding ant species in Texas and pest ant control, visit the Texas A&M AgriLife Extension website at urbanentomology.tamu.edu/urban_pests.html under “Ants.”
Sharon Brooks can be reached at (409) 832-1400, ext. 241.