ARS Releases New Artillery in the Fight Against Fire AntsBy Tara Weaver
May 29, 1998
A microorganism from South America is the latest biological weapon against
the red imported fire ant. ARS researchers and state cooperators released fire
ants infected with T. solenopsae this week at sites in Hope,
Ark., and Durant, Okla.
The scientists are confident that, over time, this promising biocontrol
agent can reduce fire ant numbers. The ants now infest millions of acres across
11 southern states.
The pathogen, technically a microsporidium, infects ant colonies and
chronically weakens them. Workers transmit the pathogen to the queen through
food exchange. The disease slowly reduces her weight. She lays fewer and fewer
eggs, all infected with the pathogen, further weakening the colony.
Colony elimination can take from nine to 18 months. However, in lab studies,
ARS entomologist David Williams found that after three months, infected colonies
were already significantly smaller than healthy colonies.
T. solenopsae, discovered in Brazil in 1973, is the most
common pathogen found in fire ants in South America. In 1996, ARS scientists
discovered the pathogen in fire ant colonies in Florida, Mississippi and
The microorganism doesn't harm plants or native ant species. After years of
testing, Williams has found T. solenopsae only in red and black
imported fire ants. The researchers are now working on mass-producing the
Williams and colleagues have already released the microsporidium at test
sites in Florida, along with the
Brazilian phorid fly,
another natural enemy of the fire ant. The researchers are hoping the pathogen
and fly will act as a one-two punch against the fire ants.
Other states slated for possible limited releases of T. solenopsae
include Alabama, Tennessee, South Carolina, Georgia, North Carolina, Virginia
Scientific contact: David F. Williams, Imported
Fire Ant and Household Insects Research Unit, Center for Medical,
Agricultural and Veterinary Entomology, Gainesville, Fla., (352) 374-5982,
fax 374-5984, firstname.lastname@example.org.