Controlling Red Imported Fire Ants Two Ways
Durham July 10, 2009
Two separate strategies for reducing the spread of red imported fire
ants (RIFA) are being combined by Agricultural Research Service (ARS)
scientists as part of a strategy that could potentially add to the arsenal
against this spreading pest.
Currently, parasitic phorid flies are used in the United States to
help control some fire ant populations. In Argentina, pathogens like
Kneallhazia solenopsae and Vairimorpha invictaealone or in
combinationare associated with localized declines of 53 to 100 percent in
fire ant populations, according to entomologist
Oi, at the ARS
for Medical, Agricultural and Veterinary Entomology (CMAVE) in Gainesville,
Now, ARS scientists are looking to add a new scientific wrinkle: using
the phorid fly as a vector for infecting the fire ant population with
Each phorid fly lays an egg into individual fire ants. These eggs
later develop within the fire ant's head, ultimately causing its demise. But
researchers tested a new methodinfecting the phorid flies with a
pathogenic microsporidia that controls fire ants.
Preliminary data showed that K. solenopsae was successfully
transmitted to phorid flies without harming them. The next step is to determine
whether infected flies are able to infect RIFA with the microsporidia,
providing another mechanism for transmission between RIFA colonies.
According to Oi, K. solenopsae not only reduces fire ant colony
size, it also reduces successful colony founding by reproducing ants, affects
the survival of queens and increases the death rate of colonies.
Oi conducted this research with entomologists
Valles at CMAVE, and with Juan Briano and Luis Calcaterra of the
South American Biological Control Laboratory in Hurlingham, Argentina.
about this research in the July 2009 issue of Agricultural Research
ARS is the U.S. Department of
Agriculture's principal intramural scientific research agency.