announced that a biological control program to control imported fire ants
is being initiated in Immokalee and Sarasota.
"Imported fire ants can deliver painful bites, and we're pleased to be part
of the team that is addressing their growing population in Florida,"
Bronson said. "The insect that is being reared in our Biological Control
Rearing Facilities is a small fly that packs a powerful punch to these
ants."
The program currently under way in Immokalee is a cooperative effort. It
is being administered by Professor Phil Stansly of the University of
Florida's Southwest Florida Research and Education Center. The U.S.
Department of Agriculture funds the Florida Department of Agriculture and
Consumer Services' Division of Plant Industry in Gainesville to produce and
distribute the flies. The Division of Plant Industry's Bureau of Methods
Development and Biological Control serves a valuable function in applying
biocontrol technology by working out mass-rearing and release techniques.
The division has environmental specialists stationed throughout the state
to monitor the effectiveness of biocontrol programs.
Phorid fly releases began in north central Florida in 1997. By fall 2002,
the phorid fly population had expanded coast to coast in northern Florida
and southern Georgia. While it is likely that the population of imported
fire ants has decreased in these areas, it will take three to four more
years to accurately measure the impact. As flies become available through
the rearing process, Bronson said he hopes to continue the release program
throughout Florida, including another release tentatively scheduled for
later this month in Sarasota.
The program, based on research by Sanford Porter, an entomologist with the
U.S. Department of Agriculture, introduces South American phorid flies, a
natural enemy of the imported fire ant, to the United States. The flies
inject their eggs into the fire ants. When an egg hatches, the maggot finds
its way into the ant's head, where it grows for two to three weeks before
secreting a chemical which causes the ant's head to fall
off. The maggot eats everything in the head capsule, then uses it as a
pupae case. The phorid flies eventually emerge from the decapitated ant
heads to seek out their host species, the imported fire ant. The phorid
fly presents no threat to people, animals or plants.
The Immokalee program will last for approximately 10 days with the flies
being released daily over excavated ant mounds. In that time, a sufficient
number of ants should be parasitized (meaning the flies' eggs have been
deposited in the ants), so that establishment of the fly population is more
likely.
Imported fire ants, which differ from a less common native species of fire
ant, were accidentally introduced into the United States from South America
70 years ago and have had a major impact. The ants are capable of multiple
stings which inject venom that raise white pustules on skin. The ants also
cause crop and equipment damage, livestock losses and soil erosion
problems, and are particularly dangerous on playgrounds, lawns, golf
courses and pastures.
Efforts to eradicate these ants have been ongoing for more than 50 years.
However, their range continues to expand and they have spread to most
southern states. There are poisons available that kill them on contact or
by ingestion, but these poisons also kill many non-target ants and other
beneficial insects. Unlike poison, using the phorid fly is safe for
people, animals and crops.
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