Georgia farmers are using a new way to grow cotton that
keeps bugs at bay
while protecting the environment.

They’re growing a new type of cotton, called Bt cotton,
that fights some insects
while it grows.

Phillip Roberts, an entomologist with the University of
Georgia Extension
Service, expects Georgia farmers to plant about a third of the
1997 cotton crop to Bt
varieties.

Farmers include Bt cotton, Roberts said, in an overall
insect-control method
called integrated pest management.

IPM programs use all sorts of natural controls,
including Bt cotton and
beneficial insects, instead of chemicals to keep insects from
harming the crop. Cotton
growers may still have to use some pesticides, but only as a
last resort.

IPM helps farmers stay on friendly terms with people who
live around them,
too. It can cut down on the number of times farmers must spray
pesticides. Neighbors
like that.

Bt cotton can cut out even more spraying. It produces
its own natural toxin that
helps control certain insects on the plant.

Scientists took a toxin-producing gene from bacteria
called Bacillus
thuringiensis (Bt). They inserted it into the new cotton
plant that takes its name.

The naturally produced toxin helps control insects. “Bt
cotton and IPM
programs don’t guarantee ‘no sprays,’” said Steve Brown, an
extension cotton
agronomist. “But they can dramatically decrease the number of
applications required.”

Killing bugs with the Bt toxin isn’t new. Many gardeners
use it, too.
Laboratories collect the toxin and include it in foliar sprays
for garden plants. The toxin
is the same. Only the delivery method differs.

Now that the Boll Weevil Eradication Program has
banished weevils from
Georgia cotton fields, Roberts said farmers can really take
advantage of the Bt
technology.

“Regular cotton varieties might require six or seven
pesticide applications in a
given year to control insects,” he said. “A field of Bt cotton
right next to the regular
variety may only need two or three applications for the same
amount of insect control.”

One concern many people have is that insects may become
resistant to
pesticides. Gary Herzog, a research entomologist at the Coastal
Plain Experiment
Station, said IPM and Bt cotton can slow that process.

Herzog has studied insect pesticide resistance trends
since 1979.

“Usually, a particular chemical can be widely used for
about 10 years before
resistance shows up,” he said.

Bt cotton can extend that time. Farmers don’t have to
spray as often. So insects
aren’t exposed as much to the most commonly used pesticides. So
it takes them longer
to develop resistance.

If the Bt toxin doesn’t kill all the insects, Herzog
said, it still weakens
survivors. That makes them more vulnerable to other insecticides
and the beneficial
insects that prey on them.

The Bt toxin doesn’t affect the cotton fiber. It’s as
strong and long and white as
that of non-Bt varieties.

Planting Bt cotton can help farmers’ profits, too. If
they can grow cotton with
lower cost per acre, they can make more money on the same
land.

Higher profits lead more farmers to grow cotton. When
more cotton is sold,
though, the farmer’s prices can drop. Retail cotton clothing
prices can drop, too.

It costs farmers more — about $33 per acre — to plant
Bt cotton. Roberts and
Brown said if a grower has to spray a field four or more times
for bollworms, he may
do better planting Bt cotton.

“Each farmer has to decide if he can control bollworms
for less than the cost to
plant Bt cotton,” Brown said.