A year ago, agriculture officials declared the boll weevil
nonexistent in Georgia. And partly
because of the weevils’ demise, cotton acreage blossomed to
almost 1.5 million acres this year.
But as farmers harvest the most cotton acres since 1949,
they may be giving their old nemesis a
new lease on life.
“This extremely high production has forced some growers to
lease harvest equipment used in other
states,” said Bill Lambert, an entomologist with the University
of Georgia Extension Service.
“The Boll Weevil Eradication program may not be complete or
even started in those states,” he
said, “and producers may be inadvertently bringing boll weevils
back into Georgia cotton fields.”
Other Southeastern states have the same problem. Boll
weevils crossed the Rio Grande into
Texas cotton fields a century ago. Moving at about 25 miles per
year, weevils arrived in Georgia
fields in 1917. The state was considered fully infested in
1925.
In the 1980s, the Boll Weevil Eradication Program helped
turn the tide on the devastating insect.
The Georgia eradication program began in 1987. It’s conducted
and financed by the USDA Animal
and Plant Health Inspection Service and regional and local
producer associations.
Now, only a few Georgia counties report seeing any boll
weevils at all. But the pests could become
more widespread as growers move harvesting equipment from
infested states.
Cotton bolls containing weevil grubs may lodge in
harvesting equipment. “If a farmer cleans out a
picker used in an infested field while he’s in a clean field,”
Lambert said, “he may be releasing weevils
back into Georgia cotton.”
Late in the season, female weevils lay eggs in unopened
bolls. The grubs winter there until the next
spring, then emerge as adults and start reproducing. “It
only takes two weevils to have the start of
an infestation,” Lambert said.
A single fertile female can lay 200 to 250 eggs during her
lifetime. A new generation emerges
every three weeks, allowing seven generations in Georgia’s
growing season, from June 1 to Oct. 31.
Lambert figures one reproducing pair can multiply into
more than 12.8 quadrillion weevils in just
one growing season. “That’s why it’s crucial to detect the
insects early and get them under control,” he
said.
Weevils destroy the pulpy material inside the unopened
boll — the part that eventually becomes
cotton fibers. They virtually wiped out crops all over the
cotton belt in the 1920s and ’30s.
“It’s in everyone’s best interest to keep weevil
populations down in neighboring states,” Lambert
said.
Elimination plans include destroying any stalks or
unopened bolls that remain in a field after
harvest. Plants left standing may not rot and then provide a
safe wintering habitat for weevil grubs.
Most farmers mow stalks right after harvest, but the stalks
may keep growing and produce fruit that
could harbor weevils. Lambert said growers should go a step
further and harrow plants under.
Georgia is in a containment phase of the eradication
program. In July, officials placed one weevil
trap in every 10 acres of cotton. In any field where weevils are
found, trap numbers are increased to
one per acre and an intensive chemical insecticide treatment
begun.
While the pesticide quickly brings weevil populations under
control, it also kills beneficial insects.
“This is an emergency-type situation,” Lambert said. “The
weevils must be brought under control
first. Then we help the producer handle any other control-
related problems.”
In the meantime, growers should be extra careful about
bringing in out-of-state equipment.
“We’re not positive that’s how they’ve come back in,”
Lambert said, “but it’s a good place to start
and strengthen preventive efforts.”
