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Published on 11/13/95

Boll Weevils Moving Back into Georgia?

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."