Home Page Link AgBioWorld Home Page
About AgBioWorld Donations Ag-Biotech News Declaration Supporting Agricultural Biotechnology Ag-biotech Info Experts on Agricultural Biotechnology Contact Links Subscribe to AgBioView Home Page

AgBioView Archives

A daily collection of news and commentaries on

Subscribe AgBioView Subscribe

Search AgBioWorld Search

AgBioView Archives





August 22, 2000


BT and Monarchs


20 percent of monarch larvae eating milkweed in or around corn fields
supposedly died. But what percentage of them would have died had chemical
pesticides been sprayed on these same corn fields?

Write to CBS News by going to


Date: Aug 22 2000 17:18:49 EDT
From: "James N. Siedow"
Subject: Monarch larvae/Corn pollination

I just got through reading the Oecologia paper by Hansen and Obrycki and
while there are several issues I would take with it, I would be interested
in tying to get one thing clarified. The first paragraph of the Discussion
refers to there being a high degree of overlap between the appearance of
Monarch larvae and corn pollination throughout the corn/Monarch belt. I
was of the impression from material I had read previously on the topic
(e.g. that came out of the Monarch Symposium held this past spring) that
one of the arguments against Bt-corn being a problem was the infrequent
overlap in many parts of the country between when corn sheds its pollen and
Monarch larvae are feeding. Hansen and Obrycki say this ain't so. Does
anyone have some insight into this discrepancy?

James N. Siedow Ph: (919) 613-8180
DCMB/Biology FAX (919) 613-8177
B354 LSRC E-mail: jsiedow@duke.edu
Research Drive
Box 91000
Duke University
Durham NC 27708-1000

Date: Mon, 21 Aug 2000 17:20:52 -0500
From: tony.minnichsoffer@seeds.Novartis.com
Subject: Bt corn and Monarch butterfly

Dear Colleagues,

Attached are a letter from Ed Shonsey and a backgrounder from Novartis
Seeds, Inc. which we hope you will find helpful in view of the current

Please call or email me with any additional questions.
Thanks. Sincerely,
Tony M.

|Tony Minnichsoffer, Communications |Tel (763) 593-7128 |
|Manager |Fax (763) 593-7154 |
|Novartis Seeds, Inc. |Web site: www.nk.com |
|Field Crops ? NAFTA | |
|7500 Olson Memorial Highway | |
|Golden Valley, MN 55427 | |
| | |
|P.O. Box 959 | |
|Minneapolis, MN 55440 | |
|e-mail: | |
|tony.minnichsoffer@seeds.novartis. | |
|com | |

August 21, 2000

To Our Industry Colleagues and Food Chain Friends:

Little more than one year ago, a single laboratory study set off a
firestorm of concern about the impact of genetically improved corn pollen
on Monarch butterfly larvae. That research, led by Dr. John Losey of
Cornell University, suggested that Monarch larvae force-fed milkweed
coated in Bt corn pollen might die.

In the ensuing months, Novartis Seeds joined with others in the industry
to fund independent research by 20 leading entomologists at 10
universities across the U.S. and Canada -- research designed to gain real
world answers to the theoretical possibilities suggested by Dr. Losey and
his colleagues. What they found by a preponderance of
evidence was that, under actual field conditions Bt corn pollen has little
impact on Monarch butterfly populations. These researchers presented their
independent findings in scientific forums such as the Entomology Society
of America's annual meeting, providing opportunity for peer-review,
discussion and debate. The research will continue
for another year to ensure data integrity and an appropriate level of
scientific input.

This week, CBS Evening News plans to air a report on a "new" study whose
findings are contrary to this body of evidence. This time, the lead
researcher is Dr. John Obrycki of Iowa State University and, similar to
Losey's research, this study appears to be based on an experimental design
that has questionable relevance to what Monarch
butterflies will encounter under actual field conditions.

The reality is that the Obrycki study, like Losey's work last year, offers
no new insights into the Bt corn discussion. During its initial review of
the technology, officials at the Environmental Protection Agency (EPA)
evaluated the risk of Bt corn pollen and its potential impact on other
insects. At that time, they concluded that the benefits of Bt corn far
outweighed any theoretical risk to non-target species. This risk
assessment was once again upheld
earlier this month when the EPA extended its registration of these Bt corn

Novartis Seeds, in cooperation with industry colleagues, has provided the
CBS reporter with additional scientific information, in an attempt to help
him weigh the relevance of Obrycki's findings against the mountain of
contrasting evidence, including that generated to date from the
comprehensive institutional study described above. We hope the news story
will reflect a balanced assessment of the facts.

The CBS news report is slated to air Monday, August 21.

Overview of Research Presented at the Monarch Butterfly Research Symposium

Public discussion of the impact of Bt corn on monarch butterfly
populations was originally spurred by a single, four-day laboratory study
conducted by Dr. John Losey of Cornell University and published in the May
20, 1999, issue of Nature. In the study, monarch larvae fed milkweed
leaves artificially coated with Bt corn pollen ate less, grew slower and
suffered a higher death rate than larvae that consumed milkweed leaves
free of corn pollen.

By design, Losey's research did not mimic natural conditions. In the
laboratory, the caterpillars were given no choice but to feed on leaves
artificially covered with corn pollen. Under actual field conditions, a
complex series of events must fall into place for there to be even a
possibility that Bt corn pollen may cause any harm to monarchs.

The monarchs must be in their larval development stage, a period which
last just 12 to 16 days. The monarch larva must be feeding at the same
time corn is pollinating, a narrow period of seven to 10 days. The
milkweed plant that the larva feeds on must be located near a Bt
cornfield. Bt corn pollen must fall on the particular milkweed leaf that
the caterpillar is feeding on. The caterpillar must consume the pollen
before rain or dew washes it away.

To determine what impact, if any, Bt corn pollen has on monarchs in their
natural environment, a coalition of leading scientists from government,
universities and Extension fielded a series of independent studies in
1999, and continued their work in 2000. The results of their initial
studies were presented on Nov. 2, 1999, at the Monarch Butterfly Research
Symposium in Chicago. Key findings from this extensive body of field
research include:

Monarch migration and Bt pollen shed may not coincide. For many areas of
the U.S., June is the peak time when the first generation of Monarch
larvae are actively feeding on milkweed plants. In contrast, the peak time
of corn pollen shed is typically mid-July through early August. To
evaluate the potential interaction between later generations of Monarch
larvae and Bt corn pollen, Dr. Galen Dively, pest management specialist
and professor of entomology at the University of Maryland, monitored
Maryland cornfields and monarch development in 1999. He found that corn
plants had completed pollen shed before later generations of monarch
caterpillars were first
observed feeding on milkweed. Similarly, Dr. John Foster, professor of
entomology at the University of Nebraska, observed that by late July, corn
pollination in Nebraska was 95 percent complete before monarch eggs were
observed on milkweeds near corn. Monarchs prefer milkweed away from corn.

Tests by Dr. John Losey, Cornell University assistant professor of
entomology, show that monarchs avoid laying eggs on milkweed surrounded by
corn. Further, researchers from USDA-Agricultural Research Service (ARS)
and Iowa State University found that when given a choice between feeding
on milkweed leaves with no pollen or high levels of Bt pollen, the
majority of monarch larvae chose no pollen.

Corn pollen doesn't travel far. Researchers at Stanford University,
University of Guelph, Iowa State University and
University of Maryland conducted independent studies to evaluate the
spread of corn pollen. In each case, the scientists found that corn pollen
levels decrease rapidly a short distance from the field edge.

Milkweed density is highest along roadsides, not corn fields. Dr. Doug
Buhler, research agronomist for USDA-ARS and Dr. Robert Hartzler,
associate professor and Extension weed scientist at Iowa State University,
found that Iowa roadsides typically had 48 common milkweed patches per
hectare, while corn and soybean fields had only
seven patches per hectare.

A more detailed summary of these research findings is available at

Additionally, the following scientists could provide more information on
the relationship between monarch butterfly larvae and Bt corn pollen:

Dr. Dennis Calvin, Pennsylvania State University, (814) 863-4640

Dr. Chris Difonzo, Michigan State University (517) 353-5328

Dr. Galen Dively, University of Maryland, (301) 405-3919

Dr. John Foster, University of Nebraska, (402) 472-8686

Dr. Rick Hellmich, USDA-ARS, Iowa State University, (515) 294-4509

Dr. Michael Phillips, Executive Director, Food & Agriculture,
Biotechnology Industry Organization, (202) 857-2306

Dr. John Pleasants, Iowa State University, (515) 294-7204

Dr. Marlin Rice, Iowa State University, (515) 294-1101

Dr. Mark Sears, University of Guelph, (519) 824-4120

Dr. Warren Stevens, Missouri Botanical Garden, (314) 577-5103

Dr. Tom Turpin, Purdue University, (765) 494-4554