May 5, 2000

There’s a fungus among us, and researchers at Texas Tech University are proving it to be fatal to fire ants across the state. Entomologists in the plant and soil science department say the deadly fungal bait has been extremely effective in killing fire ants in the Texarkana area as well as at other field test sites.

Texas Tech scientists began working on a biological control for fire ants 10 to 12 years ago, said Harlan Thorvilson, Ph.D., professor of entomology. The project isolated a common soil fungus that attacks only insects. To see if the fungus bait formulation was responsible for killing fire ants, Texas Tech scientists genetically altered it to include an enzyme that indicated the presence of the fungus in the dead ants.

"We then found a way to encapsulate the vegetative material in the fungus, called mycclia, into a pellet. We were able to dry down the pellet, or dehydrate it, so that they’re like Grape Nuts, then store it," said Thorvilson. "The fungus reactivates by rehydrating it with moisture, it starts growing nicely, starts to produce spores, and the spores are deadly to fire ants."

Thorvilson said Texas Tech’s main field research took place in Texarkana. Field trials also are set for independent sites in College Station, Gainesville, Fla. and Gulfport, Miss.

"The general idea of the fungus is to broadcast it over a field where there are many colonies. When the ants go to investigate the food, they find these pellets. They are attracted to the pellets, pick them up and deliver them to their colony. In the moist underground of the colony, the pellets rehydrate, produce spores and kill off the ants," Thorvilson said.

The heaviest populations of fire ants in Texas are east of Interstate 35, with the longest established colonies appearing in the Houston area. Colonies closer to Lubbock and Texas Tech University are located in the Abilene and San Angelo areas. Thorvilson believes the fire ants were probably brought to West Texas in nursery plant material.

The entomologist said Texas Tech’s biological attack on fire ants through application of fungal bait is just one weapon in the fight to eradicate them.

"As soon as we’re ready to bring on a commercial partner and market this product, it will be another tool in our pest management tool box. Used in conjunction with insecticides, parasites and other means of control, we might be able to suppress them enough to alleviate some of the economic damage they cause," he said.