By Faith Peppers
University of
Georgia
Football games aren’t the only struggles cranking up on grass
battlefields now. University of Georgia experts say fall is an
ideal time to fight fire ants, too.
“It’s appropriate to treat for fire ants anytime that they’re
active,” said Dan Suiter, an entomologist with the UGA College
of Agricultural and Environmental Sciences. “They’re active in
warm months.”
Since it stays warm well into the fall in the South, keep up
the fight.
“You hear about fall treatments sometimes in light of baiting
programs,” Suiter said. “Many of the baits registered for fire
ant control are very slow-acting growth regulators. It may take
a half year or more to eliminate the colonies. So, the thinking
is to bait in the fall, and the next spring the ants will not
return.”
New weapons
Red imported fire ants first made an appearance in Georgia in
the early 1950s. By 1987 they had spread to 143 of 159
counties. Today the entire state is infested, as is much of the
East Coast to southern Virginia.
“While the basic biology of fire ants hasn’t changed, there
have been some advances in control techniques and materials,”
said UGA entomologist Will Hudson.
“Baits remain the best options for large areas (more than 1
acre or so),” he said.
Many brands fall into two basic groups: those with active
ingredients that are toxic to the ants (like Amdro) and those
that have as active ingredients insect growth regulators that
sterilize the queen and stop development of the immature ants
in the colony.
“Baits work by taking advantage of the ants’ behavior,” Hudson
explained, “so we can apply a small amount (1 to 1.5 pounds per
acre) of material and let the workers take it back to the mound
and feed it to the colony.”
No mounds v. no ants
Applied every six months, they often carry a guarantee of “no
mounds” if applied correctly. Not “no ants,” but “no mounds.”
“As it happens, it takes about six months for a colony to grow
from the founding queen to a size where there are enough
workers to build the characteristic mound,” he said, “and the
baits are good at breaking the cycle. There will, however, be
ants there between applications, just not all that many.”
Bait treatments generally cost $20-30 per acre.
For smaller areas, or where you need zero ants, Hudson
recommends a broadcast application of a contact insecticide.
“The best of these include fipronil products such as Over’n’Out
for homeowners or those with pyrethroids as active
ingredients,” he said.
Pyrethroids are active ingredients ending in -thrin such as
bifenthrin, permethrin, cypermethrin or cyfluthrin.
“There are lots of these on the shelves, as they’re all off
patent now,” Hudson said.
“Fipronil will usually give a season of ‘no ants,’” he
said. “The pyrethroids are less long-lasting, but will give 1
to 3 or even 4 months of control. After that, the cycle starts
over if the ants are flying (almost all year in south Georgia
and April through October in Atlanta).”
Costs range from less than $50 per acre for pyrethroids to more
than $150 per acre for fipronil. “But, if your yard is 5,000
square
feet, they aren’t that expensive,” Hudson said.
A newcomer to the fire ant control market is indoxacarb, which
is sold as Advion for commercial use and in the Spectracide
line for homeowners. “It’s a bait, but instead of weeks to see
a reduction in ants, they start to disappear in a couple of
days. It’s still a ‘no mounds’ type, but fast,” Hudson said.
