No new ecological problem expected with Fire Ants

Wednesday, October 27th 1999, 12:00 am
By: News On 6

OKLAHOMA CITY (AP) -- A fly imported to kill alien fire ants may
not survive the winter.

Researchers recently unleashed Brazilian flies in Bryan County
that are the natural predators of South American fire ants. The
ants have been migrating slowly northward in Oklahoma and other

Although results of the release could be a year or more away, it
remains to be seen whether the tiny Phorid fly -- or Pseudacteon
tricuspis -- can survive an Oklahoma winter, Russell Wright, head
of Oklahoma State University's Entomology and Plant Pathology
Department, said Tuesday.

The flies have lived through winters in warmer climates in Texas
and elsewhere, he said, and researchers hope the insect survives in
Oklahoma to help fend off the fire ant.

The South American fire ant is thought to have landed in the
United States in the early 1930s and has since spread to 11 states.
It is considered a threat to livestock, crops and people with

The ants have flourished in the United States because the insect
lacks a natural enemy here, officials have said

The female Phorid fly is about one-sixteenth of an inch long,
lives up to two weeks and can kill about 200 fire ants by stinging
them and depositing eggs in their bodies.

The fly larva grows and moves to the host's head where it
matures and decapitates the fire ant.

However, the ants rid their dens of the dead and could toss out
a developing fly, which might freeze to death, Wright said.

But a natural enemy of the fly -- cold -- may also deter the
fire ant, said Don Molnar, program administrator for the Oklahoma
Agriculture Department.

"We don't know if a good cold winter will wipe out the northern
edge of where they are now," Molnar said.

U.S. Department of Agriculture researchers have studied the
Phorid fly in detail and are certain it will kill only the fire ant
and won't otherwise create ecological havoc.

Indigenous ants, which also help control the fire ant
population, shouldn't be threatened by the tiny fly, Wright said.

"The ones we're introducing will only kill the fire ant," he

Ants are territorial. Native ants kill fire ants and also
compete with them for food, he said

Officials have cautioned against the widespread use of
pesticides to eradicate the fire ant for fear that the chemicals
would also kill native ants, Wright said.

The state and federal officials have quarantined eight southern
Oklahoma counties -- McCurtain, Bryan, Marshall, Love, Carter,
Choctaw, Johnston and Comanche.

Shipments of nursery plants, heavy equipment and some hay must
be inspected before leaving the counties, Molnar said.

Inspecting shipments may only slow their northern migration, he
said, because reproducing fire ants can fly.

The fire ant will not be eradicated, Wright said, but can be