A brave new cotton is getting mixed reviews as its first big
Georgia harvest
approaches. But any critique is too early until all the cotton
is picked, says a
University of Georgia Extension Service expert.

"We still have many growers who are very happy with the
product," said
Phillip Roberts, an extension entomologist. "However, we
also have some who are
displeased. But we won’t really be able to evaluate it until the
harvest is in and we know
what kind of yields we’ve got."

The new cotton is a modern wonder. Using genetic engineering,
scientists inserted a
gene from a bacterium, Bacillus thuringiensis, into
cotton plants. This Bt gene
allows the plant to produce a toxin common in nature. In a
sense, the new cotton grows its
own insecticide.

The toxin is deadly to tobacco budworm and helps control corn
earworm, the two main
insect pests of Georgia cotton.

So far, growers’ assessment of Bt cotton varies from place to
place. But Roberts said
it’s not over until the cotton is picked. The harvest is Bt
cotton’s final exam.

"We may still have better yields with Bt cotton because
of the bollworm control it
provides," he said. "So we can’t really give it a
final grade until then."

The Boll Weevil Eradication Program chased the worst cotton
pest, the weevil, out of
Georgia by 1994. "Since then, our farmers have spent more
money controlling tobacco
budworm and corn earworm than all others combined," Roberts
said.

The two caterpillars are both called bollworms when they
attack cotton.

"You really can’t distinguish between the two when
they’re small," Roberts
said. "When they’re adults, though, you can."

Bt cotton made its debut this year across the cotton belt.
The seed cost growers more
than normal varieties. But they figured to come out ahead, since
they wouldn’t have to
spray costly insecticides to control bollworms.

That hasn’t been entirely true, partly because of an oddity
among bollworms.

"Tobacco budworm is more susceptible to Bt than corn
earworms," Roberts said.
"Normally we have a fairly even mix between the two. But
this year the population is
skewed heavily toward corn earworms."

No one knows what happened. "Something happened over a
large area of the cotton
belt that reduced tobacco budworm populations," Roberts
said. "But we don’t know
what that was."

The result is that Bt cotton’s control of bollworms has
disappointed some growers.

"We have some Bt cotton that hasn’t been sprayed at all
for bollworms," he
said. "In other areas, growers have had to spray once, and
sometimes twice."

Statewide, Roberts said, farmers have had to spray for
bollworms in about a fourth of
the Bt cotton. "One of the things we’ve learned this
year," he said, "is
that Bt cotton isn’t immune to bollworms."

Some conventional cotton fields haven’t had to be sprayed
this year. Others have been
sprayed up to six times. The state average, Roberts said, is
probably around three sprays.

If Bt cotton does prove successful, it could add to the
supply U.S. farmers grow. But
it may not affect the price of cotton products at the store.

"The main benefit would be a lower cost to
farmers," Roberts said. "That
would give them a better profit for all the work and risk of
growing cotton."