Thought this might interest, from the UW College of Ag's Press
------- Forwarded Message Follows -------
Date: Mon, 16 Sep 1996 15:06:24 -0500
To: [distlist snipped]
From: email@example.com (Bob Cooney)
Subject: UW SCIENTISTS URGE CAUTION ON GENETICALLY ENGINEERED CORN
For Immediate Release
For More Information:
Joe Lauer (608) 263-7438
John Wedberg (608) 262-3226
UW SCIENTISTS SAY Bt CORN WORKS, BUT THEY URGE CAUTION
University of Wisconsin-Madison agronomist Joe Lauer and
entomologist John Wedberg are finding that new corn hybrids that make their
own insecticide are protected from European corn borers - corn's major
insect pest. But the scientists stop short of giving the hybrids a blanket
"The technology is truly amazing," says Lauer. "It may well
revolutionize how farmers grow corn. But I don't think farmers should 'bet
the farm' on these new genetically altered corn hybrids yet."
A small amount of CIBA Seeds' new Bt corn was available to farmers
this year. Northrup King will market its version of Bt corn next year.
Wedberg estimates that the two companies will market enough Bt seed to
plant 3 million to 6 million acres of corn in the Midwest next year.
Lauer and Wedberg are testing several of CIBA Seeds' and Northrup
King's new hybrids with the Bt gene. The gene, first identified in the
bacterium Bacillus thuringiensis, codes for a crystal protein that is
toxic. Scientists have identified about 70 toxins from different bacterial
strains, according to Wedberg. In general, Bt toxins kill certain types of
insects but are harmless to people and livestock.
Plant scientists in universities and industry have moved Bt genes
into economically important plants, including corn, cotton, cranberries and
In 1995 Lauer and Wedberg evaluated Bt corn hybrids at the College
of Agricultural and Life Sciences' Arlington, Hancock and Lancaster
Agricultural Research Stations. This year they are again testing them at
Arlington. Corn borer populations in both years have been very high.
The Bt hybrids from CIBA and Northrup King were virtually untouched
by European corn borers in 1995, even though Wedberg inoculated some corn
plants with borer egg masses four times during the summer. Lauer says the
Bt hybrids stood up well and the grain dried down well.
Inoculating the corn with borers resulted in yields that averaged
14 bushels per acre more for the Bt hybrids than DeKalb DK512 and Golden
Harvest H2387 at the three sites. The latter two non-Bt hybrid standards
were grown with the Bt hybrids but not sprayed with insecticide for borers
in last year's trial.
Although the 1996 data won't be available until December, both
researchers expect the results to be similar to 1995. Despite these
results, both have some reservations about Bt corn.
Lauer's main concern is that inserting a gene into a crop hybrid
often initially depresses its yield. He calls it yield lag. "It may take
seed companies several years before their genetically engineered hybrids
yield as much as existing hybrids," he says.
Also, Lauer is frustrated that seed companies have not put their Bt
lines up against other hybrids in University of Wisconsin field trials.
"We compare about 200 hybrids in trials across southern Wisconsin.
We have no idea how the Bt hybrids would do in this mix, which includes
hybrids that have been bred for improved stalk strength so they too can
withstand borer attacks," he says.
"To test the Bt corn, a farmer could plant 5 or 10 acres of the
corn and see how it performs on the farm for at least two years before
making a big investment in it," Lauer says.
Even though the Bt corn seed is expected to cost only $5 to $8 per
acre more than other hybrids, Wedberg wants to evaluate if farmers can be
as profitable with current farm management as they can with the new Bt
"There are parts of Wisconsin where corn fields historically
average less than one borer per corn plant going into the winter," Wedberg
says. "In those areas, borers are not likely to cause more than a 5-percent
reduction in yield. Farmers there may want to think twice about changing
Wedberg is very concerned that borer populations may become immune
to the crystal toxin in the Bt hybrids. Unanticipated problems this year
with Bt cotton in eastern Texas have raised fears that this tool for
protecting plants from insects may not work as expected.
Wedberg and other scientists worry that widespread plantings of Bt
crops may foster the development of insect populations resistant to Bt.
This has already happened with many other insecticides, according to
Widespread use of a single insecticide initially kills most insect
pests. However, it immediately begins to select for the few individual
insects, which for unusual genetic reasons, can tolerate it. When these
survivors breed, they quickly multiply and form a population resistant to
"We know now that we can't rely on a single strategy to control
insect pests," Wedberg says.
Slowing down the selection of insects able to resist an
insecticide, thus keeping pesticides effective, is part of an important new
specialty called managing pest resistance.
"Farmers, educators and seed companies all have the same goal
here," Wedberg says. "We all want to keep this new tool available to
farmers for as long as possible."
Wedberg says the way to keep Bt corn effective against borers is to
plant non-Bt hybrids on a substantial fraction of Wisconsin's corn acreage.
"When the seed becomes widely available, we will urge farmers to plant
non-Bt hybrids on a quarter of their corn acreage," he says. "We hope this
will keep the corn borers from developing resistance to Bt corn."
Bt corn 9-16-96
Writer: George Gallepp (608) 262-3636
Bob Cooney, editor
Department of Agricultural Journalism
University of Wisconsin-Madison
440 Henry Mall
Madison WI 53706
phone 608-262-2679, fax 608-265-3042
Michele Gale-Sinex, communications manager
Center for Integrated Ag Systems/Ag Technology and Family Farm Institute
UW-Madison College of Ag and Life Sciences
Voice: (608) 262-8018 FAX: (608) 265-3020
Dreams and nightmares are made of the same material.
But this nightmare purports to be the only dream
we're allowed: a development model that scorns life
and idealizes things. --Eduardo Galeano