At this year’s annual Sunbelt Agricultural Exposition, Tim Davis, Clemson University county Extension agent and area-wide fire ant specialist, will demonstrate to farmers as well as other Expo attendants how to suppress fire ants.
According to Davis, who started the South Carolina Area-Wide Imported Fire Ant Suppression program, the most common question he ever received as a county agent was about fire ants and how to control them.
“As I learned about them, I found them to be fascinating creatures,” he says, “and I soon returned to graduate school to do research on fire ant biology and ecology.”
There are several main objectives in the suppression project. These objectives include the release and spread of natural enemies for fire ants, integrating the use of baits and biological control to provide 80-percent sustained area-wide reduction of fire ants, save at least $4 billion a year in the cost of fire ant control and damage, reduce reliance on repeated applications of insecticides, and restore ecological balance in the natural environment.
Cooperating states in the suppression effort include Florida, Mississippi, Oklahoma, South Carolina and Texas. The locations for the fire ant suppressant are two 300-acre sites of pasture in each cooperating state with heavy fire ant infestations.
Davis says there are two species of decapitating flies being released as they become available, and they are considered the natural enemies of fire ants. As well as flies, there is another natural enemy in the form of a protozoan disease called Thelohania.
Both of these biological control organisms kill fire ants in their native South America, but they are still new to the United States. The USDA-ARS has imported, isolated and mass-produced these organisms for release.
“These are difficult to release and are not likely to be made commercially available,” Davis says. “The plan is to release the biological controls as they become available and allow them to spread on their own.”
Davis adds that in order for a natural control to be used it must first be demonstrated to be species specific.
“That means it will only survive when fire ants are present and that it doesn’t attack any other species,” he says.
The baits, which are mixed together, are effective yet expensive.
Two baits, hydramethylnon and methoprene, are combined to provide long-term suppression of fire ants. Hydramethylnon kills ants within three to five days, and methoprene bait sterilizes any reproductives and prevents larvae from developing normally.
According to the website, http://entweb.clemson.edu/fireant/, USDA-ARS has worked to make oil-based baits commercially available to the public. These baits do not harm wildlife because they break down in sunlight.
Davis says while fire ants can pose problems for several crops, the biggest impact is likely in human terms.
“It mainly affects the people that get stung and equipment that is damaged due to hitting the mounds,” he says. “Another big impact is the propensity for fire ants to damage electrical equipment.”
According to Davis, fire ants can act as predators in some crop systems such as sugarcane and cotton. In others, they can elevate the number of economic pests such as aphids, which they herd for the honeydew.
States most affected by fire ants include Southeastern states and California. Puerto Rico, Taiwan, China and Australia also are greatly affected.
According to Davis the pesticides used for fire ant control have very little impact on the environment.
“The ecological impacts of an invasive species such as fire ants are of greater concern than any of the human pollution that has occurred,” he says.
Davis says they will be treating the Sunbelt Expo site with several of the chemicals.
“We will present how we treat such areas and provide materials that anyone can use to duplicate our results on their own properties,” he says.
Farmers can rarely afford to treat for fire ants and Davis suggests they do some site analysis and treat the areas with the biggest potential impact.
“It is our hope that research into biological controls will lead to a situation that allows native ants to compete with the fire ants and reduce the fire ant population,” he says.
The suppression project is sponsored by USDA-ARS. The project at the Expo will be supported by DuPont, BASF, Valent and Welmark International. All of these companies are supplying bait product.
This year’s Sunbelt Expo is scheduled for Oct. 17-19 at Moultrie, Ga. For information visit www.sunbeltexpo.com.