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Archives
April 1-15, 2002
All about Bt corn
by Junelyn S. de la Rosa
- Bt corn is a variety of corn genetically engineered
to resist the attack of corn borers, a very destructive
and difficult to control corn pest and a relative
of common moths and butterflies.
- Bt refers to Bacillus thuringiensis, the common
soil bacteria where the gene making protein toxic
to the target insect was obtained and transferred
to Bt corn varieties. B. thuringiensis has a long
history of safe use as an insecticide.
- There are 9 types of Bt corn developed by 6 private
corporations (Table below)
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Bt corn type
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Technology developer
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Knockout, NatureGard
Yieldgard (Bt11)
Starlink
Bt Xtra
MON801
Yieldgard (MON802)
Yieldgard (MON810)
MON809
Herculex
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Syngenta Seeds, Inc.
Syngenta Seeds, Inc
Aventis (formerly AgroEvo)
Dekalb Genetics Corp
Monsanto Company
Monsanto Company
Monsanto Company
Pioneer Hi-Bred International
Mycogen (c/o Dow AgroSciences)
Pioneer (c/o Dupont) |
These Bt corn types differ in their ability to resist
the attack of their target insects and to adversely
affect non-target insects. They also differ on the
part of the plant where the Bt gene produces protein
that is toxic to the target insect, in the amount
of the Bt protein produced, the possible resistance
of the Bt protein to digestion and the possibility
of the Bt protein to cause allergic reactions. Some
Bt corn types also contain transferred gene for
herbicide tolerance.
- Bt corn, like any other genetically engineered organism
or GMO, is subject to regulation in various countries
depending on use. If planned for crop production,
environmental, food, and feed safety, data must be
generated from laboratory and field trials and reviewed
by independent scientists. If imported for food and/or
feed, data on feed and food safety must be reviewed
independently.
- The environmental safety of a particular Bt corn
for crop production is established by studying the
available information on outcrossing with wild relatives,
weediness potential, secondary and non-target effects
on humans, other vertebrates, beneficial insects and
on biodiversity and the presence of a mitigating measure
to prevent the rapid evolution of insect resistance
to the Bt protein.
- The food and feed safety considerations of Bt corn
include level of dietary exposure, comparative nutritional
composition of forage and grains, and toxicity and
allergenicity of the plant
expressed novel proteins.
- Different countries set different criteria
in approving Bt corn for planting, and processing
for food and feed use. Each type of Bt corn is evaluated
independently. Each technology developer applies for
the approval of its own individual Bt corn type.
- All nine Bt corn types were originally developed
in the USA and were approved for planting, for food
and feed use except Starlink corn that was approved
for feed use only. However, due to regulatory problems,
approval for Starlink corn was withdrawn. Approval
for Knockout, NatureGard may also be withdrawn because
of their adverse effects on swallowtail butterflies.
- Outside the USA, approvals of Bt corn for food and
feed use are as follows: EEU (counting it as one country),
Argentina, Australia, Canada, European Union, Japan,
Netherlands, Switzerland, and UK approved Knockout,
NatureGard; Argentina, Australia, Canada, European
Union, Japan, Switzerland, and UK approved Yieldgard"
(Bt 11); and Argentina, Australia, Canada, European
Union, Japan, Switzerland, and South Africa approved
Yieldgard" MON810. The other Bt corn types were
approved in Argentina, Japan, Canada except Starlink,
MON801 and Herculex I which were approved only
in the USA.
- Approvals for commercial planting of Bt corn in
other countries are as follows: Argentina, Canada,
EEU, Japan and South Africa for Yieldgard" (MON810
); Argentina, Canada, and European Union for Knockout,
NatureGard; Argentina, Canada, and Japan for Bt Xtra;
Argentina, Canada for Yieldgard" (Bt11); and
Canada, Japan for Yieldgard" (MON802) and MON
809.
- The Bt corn being tested for possible commercial
planting in the Philippines is Yieldgard (MON810).
- In Yr 2000, Bt corn was planted on 8.2 million hectares
in the USA, Canada, Argentina, South Africa, Spain
and France of which the USA has the biggest area.
- USDA estimates a significant rise in areas planted
to biotech crops especially Bt corn in the USA this
year. Biotech corn area will increase from 25% to
32%.
- All corn imports from the USA, unless otherwise
indicated, contain Bt corn because corn from various
farms are mixed in storage and processing.
- Leading importers of US corn grains and products
include Japan, Taiwan, Mexico, Egypt, South Korea,
Colombia, Saudi Arabia, Venezuela, Dominican Republic
and others like the ASEAN (Malaysia, Indonesia, Philippines,
Thailand and Vietnam).
References: http://www.essentialbiosafety.info/dbase
Bt-corn by Ric Bessin, Extension Entomologist, University
of Kentucky College of Agric http://www.uky.edu/Agriculture/Entomology/entfacts/fldcrops/ef118.htm
James, C. 2001. Global review of commercialized transgenic
crops: 2000. ISAAA Brief No. 23
Vorman, J. Biotech Crop Plantings Rise Again in 2002
Reuters Fri Mar 29, 3:24 AM ET
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All about Bt corn
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