Areawide Approach to Fire Ant Control
Durham September 11, 2007
Progress is being made in coordinated efforts to halt the spread of
imported fire ants, according to Agricultural Research Service (ARS) scientists studying this invasive pest
that now inhabits more than 320 million acres in several southern states and
Fire ants cause millions of dollars in agricultural damage each year.
Not only do they build large mounds that damage nearby plant roots and farm
equipment, they also cause painful stings to animals and people.
Valles in the agency's
for Medical, Agricultural and Veterinary Entomology at Gainesville, Fla.,
are studying two parasitic microsporidia to curb fire ant populations.
In collaboration with Juan
Briano at the ARS South American
Biological Control Laboratory in Hurlingham, Argentina, they are testing
Thelohania solenopsae. Using new genetic detection methods, they found
that worker ants transfer T. solenopsae spores to the queen. This
reduces the queen's egg production, so colonies die out.
Another microsporidium, Vairimorpha invictae, has successfully
destroyed ant colonies. According to Oi, studies have so far shown that V.
invictae doesn't infect non-fire ants or other arthropods collected in
Argentina, so it may be suitable for release in the United States.
To abate the progression of fire ants across the southern United
States, an areawide project is in place. Participants include
USDA's Animal and Plant Health Inspection
Service, state agencies and land-grant universities.
Thus far, the most successful tactic in the areawide project is the
release of tiny phorid flies. These flies pursue their targets, intent on
laying a single egg inside each fire ant's body. After two to three weeks, the
fly maggot decapitates the ant and turns into a pupa inside the ant head. The
fly that ultimately emerges repeats the process. Three phorid fly species have
been established in the United States, with a fourth awaiting field release
later this year.
about this research in the September 2007 issue of Agricultural Research
ARS is the U.S. Department of Agriculture's chief scientific research