Writer: Jennifer Paul,(972) 952-9232, j-paul@tamu.edu
Contact: Elizabeth Hickman, (214) 904-3050, ba-hickman@tamu.edu
DALLAS — A parasitic fly that may help control fire ants will be released in an experiment next week west of Denton in the small town of Ponder.
On Wednesday (Oct. 23), the Texas Imported Fire Ant Research and Management Project, working with the U.S. Department of Agriculture Animal and Plant Health Inspection Service (USDA APHIS), will release the phorid fly there, in hopes of developing long-term sustainable fire ant control methods. The release will take place on the ranch of Bill and Carol Marsh.
In its homeland of South America, the red imported fire ant is kept in check by parasites, predators and diseases. Because the phorid fly (Pseudacteon tricuspis) is one of those natural enemies, researchers in the United States began to investigate the possibility of using it as a control method for this ant.
“The phorid fly female injects an egg into the fire ant’s body,” said Elizabeth Hickman, Texas Cooperative Extension agent for IPM/fire ants in Dallas and Tarrant counties. She said the fly is black with clear wings, and looks a lot like a fruit fly.
“The larva that hatches burrows into the ant’s head, where it grows and eventually releases enzymes that cause the ant’s head to fall off. Inside the decapitated head, the larva pupates and emerges as a mature fly. However, the real impact of these flies is to reduce fire ant foraging activities which, in turn, is expected to allow native ant species to better compete with fire ants.”
“Biological control holds great promise for suppressing red imported fire ant populations,” said Bart Drees, Extension entomologist and director of the Texas Fire Ant Project. “It does not promise to eradicate them. They are, after all, still present in their native South America, where they live with dozens of parasites, predators and diseases.”
“However, in South America, the red imported fire ant is just another ant’ and rarely becomes numerous enough to become a serious economic or medically important problem,” he said.
“At the release we will transport tubes with 40 flies each, release them on to mounds that have been disturbed, and then cover the mound with a plastic box,” said Hickman. “The box insures that the flies don’t immediately fly off. We will then monitor the mound for two hours, and finally remove the plastic cover. Hopefully during that time, the flies will be able to parasitize some ants to establish a population of these parasitic flies in the area.
“It will be a success if, when we come back in the spring to the release site, we find flies. That will mean they successfully overwintered at the site and continue to lay eggs.”
Phorid flies have been released at more than 20 sites statewide and have established at about six of these since the beginning of the Texas Fire Ant Project in 1998, largely by researchers at the University of Texas under the direction of Dr. Larry Gilbert. However, this will be the first release in the north central Texas area.
Until this experiment, it was uncertain if the flies — which were transported from South America and raised in the lab — would have offspring able to survive and reproduce in the wild in this part of the state.
The red imported fire ant, Solenopsis invicta, first arrived in the United States in the 1930s on ships that docked in Mobile, Ala. The pest quickly spread, reaching Texas in the 1950s, where it now infests more than 80 million acres, mainly in the eastern two-thirds of the state. Across the South, it infests more than 310 million acres.
Overall, the pest causes approximately $1.2 billion annually in agricultural losses, ecological damage and chemical control costs, according to the Texas Imported Fire Ant Research and Management Program. Its burning sting and aggressive nature make it dangerous to humans, livestock, pets and wildlife.
Controlling the fire ant population has been the goal of the Texas Fire Ant Research and Management Project — first funded by the Texas Legislature in 1997. The money was invested into research, education and regulatory programs at the University of Texas, Texas Tech University, Texas A&M University and the Texas Department of Agriculture.
Further information about biological controls and more traditional methods of fire ant control are available from county Extension agents or from the fire ant Web page, http://fireant.tamu.edu
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