| | LSU AgCenter entomologist Linda Hooper-Bui checks for signs of fire ants making a resurgence on New Orleans' Bayou St. John Levee. (Photo by Johnny Morgan) |
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| | Fire ants. (Photo by Michael A. Seymour) |
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| | LSU AgCenter entomologist Dale Pollet said people do not need to be concerned about the safety of the fire ant bait as long as directions for application are followed. (Photo by Johnny Morgan) |
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Red imported fire ants are not just a nuisance. They pose a health threat to many individuals allergic to their sting. LSU AgCenter entomologists are working to control these pests.
The red imported fire ant, sometimes referred to as a wingless wasp, has been a resident of Louisiana since the early 1950s. While fire ants have some beneficial qualities – they can reduce the numbers of fleas, ticks, termites and sugarcane borers in an area – their negatives outnumber their positives.
Children and pets often fall prey to their painful stings. They create problems for farmers and livestock producers. Their hard mounds can break farm equipment, and ants can endanger young animals.
Control methods
Homeowners use chemical means to control fire ants in their yards, but LSU AgCenter scientists are working on biological control methods.
Red imported fire ants are indigenous to South America. Because they came to the United States without their natural enemies, they have been free to flourish. No predators are keeping them in check.
Entomologists Lane Foil and Seth Johnson are studying the use of parasites and parsitoids (parasites that ultimately kill their hosts) as a means to manage fire ants.
Phorid flies attack workers in fire ant colonies. Research has shown that workers stop foraging when attacked by female phorids. This insect has been successful at decreasing colony protein consumption and reducing the number of large-sized workers.
Phorid flies were first released in Louisiana in 1999. The fly has established itself in multiple states throughout the Southeastern United States.
The scientists also are studying the use of a microsporidium, Thelohania solenopsae, which is a parasitic organism. This organism causes a dramatic decline in brood production in fire ants and reduces the life span of the ant.
The U.S. Department of Agriculture cultured and released this organism, which has spread across the Southeastern United States.
Foil also is looking at cultural control methods in pastures. He found that plowing in November significantly reduced the area occupied by red imported fire ants in pasture plots for at least five months.
“We also obtained data indicating that cultural control alone may be a management strategy for fire ants in pastures.” Foil said. “In contrast to chemical control, this strategy could be economically viable because there are no material costs and could require minimal changes in normal tillage practices.”
Integrated techniques, such as combining chemicals with biological and cultural methods, is the best way to suppress fire ants in large areas such as pastures, Foil found.
After the flood
The LSU AgCenter announced in May 2006 the beginning of the “FAST (Fire Ant Surge Threat) Prevention” program, which involves spreading fire ant control products throughout public areas in New Orleans and encouraging private landowners in both Orleans and St. Bernard parishes to do the same.
“The unique circumstances following Hurricane Katrina made it possible for us to severely curtail the repopulation of fire ants in the Greater New Orleans area,” said David Boethel, LSU AgCenter vice chancellor for research. “Without intervention, the fire ant populations could have returned to previous levels or become an even worse problem than before the hurricane. AgCenter research has shown that areawide management programs, like the FAST program, are successful.”
In monitoring the fire ant situation in Orleans and St. Bernard parishes, the fire ant team found large areas with only a few or no fire ants in Chalmette, Arabi, lower Plaquemines Parish, the Lower and Upper Ninth Wards, New Orleans East and parts of Gentilly and Lakeview.
“In adjacent areas where there was little or no flooding, relatively high populations of fire ants still existed,” Hooper-Búi said. “For the most part, the fire ants are where the people are.”
From these populated areas, both the native ants and invasive fire ants can re-colonize the once-flooded neighborhoods. However, fire ants have the advantage because they are much more aggressive and can out-compete native ants for food.
“We don’t want to get rid of the native ants,” Hooper-Búi said. “They are necessary for ecological balance.”
Fire ants are attracted to a bait that has been spread in an area and carry it back to the colony to feed the queen and the young ones. The product renders them sterile, and by attrition they disappear, said Dale Pollet, LSU AgCenter entomologist.
“You can see the suppression within 3-4 weeks,” Hooper-Búi said.
Communitywide control
For the homeowner, it is more effective if neighbors work together to manage fire ants.
“You can get good results treating on your own, but ants from other yards will eventually move back in,” Pollet said.
The entomologist recommends neighbors treat their yards on the same weekend using a growth regular.
Treat on a day when the temperatures are mild and the weather is dry.
Products to use include Amdro, Esteem and Over ‘n Out, a contact insecticide, from the GardenTech company.
“All of these products are safe as long as the labeled instructions are followed,” Pollet said. “They pose no threat to kids playing in the yard or dogs and cats. In fact, the same ingredients used in Over ‘n Out are used in flea control.”
Pollet said Esteem bait is exactly the same thing as a product called Distance, if people want to purchase it at the store.
For more information about how you can control fire ants, go to the fire ants page.
The LSU AgCenter is one of 11 institutions of higher education in the Louisiana State University System. Headquartered in Baton Rouge, it provides educational services in every parish and conducts research that contributes to the economic development of the state. The LSU AgCenter does not grant degrees nor benefit from tuition increases. The LSU AgCenter plays an integral role in supporting agricultural industries, enhancing the environment, and improving the quality of life through its 4-H youth, family and community programs.