where an insect would feed and growers
had to treat often since sunlight quickly
broke down Bt. With the advent of
genetic engineering beginning in the
1970s, scientists began to see many
different uses of this new technology in
agriculture. One of the first was to
insert Bt genes into plants so the plants
would produce essentially the same Bt
proteins that were in the foliar spray. In
1996, the first genetically engineered
Bt plants were commercialized and, by
2005, they were grown on 26.3 million
hectares. Finally, we had some plants
that were resistant to some caterpillars
and beetles! Perhaps we were on the
road forward that Rachel Carson had
advocated.
However, the road forward with
genetically-engineered insect resistant
plants has had a few bumps in it.
On the one hand, the adoption of
Bt plants has risen incredibly quickly
in several countries and has led to
dramatic reductions in the use of
“harder” insecticides, fewer pesticide
poisonings, and improved farmer
income. Additionally, the fear that
insects would rapidly become resistant
to Bt plants has not materialized even
after more than 10 years (this is in
stark contrast to nearly all other insecti-
cides). Lack of resistance to date
may be due to the wisdom of creating
Bt plants with a high enough dose
that heterozygosity for resistance would
be controlled (it is the heterozygous
individuals that drive resistance in a
population) and the requirement of
having refuges of non-Bt plants so that
susceptible alleles would be maintained
in the population.
Additional fears that Bt genes would
spread to wild and weedy relatives and
cause environmental havoc and that
non-target organisms, especially bio-
logical control agents, would be nega-
tively impacted have proven to be
unfounded. In fact, Bt plants have
advanced the use of biological control
because they have reduced the use of
broad-spectrum insecticides that are
harmful to many biological control
agents. However, regulatory issues and
acceptance of Bt plants in some
countries has been problematic. Bt
plants and other products of biotechnol-
ogy have been called everything from
“unnatural and playing God” to
“Frankenfoods.” If you asked 100
people in the general public who were
opposed to genetically engineered
plants their reasons for their position,
you’d likely get many different
answers including questions about long
term food safety issues, corporate
control of agriculture, and globalization.
Few would be knowledgeable enough to
ask or interpret the technical issues and
to analyze the risks and benefits of
using this new technology compared to
continuing with older technologies for
insect management, many of which are
far more hazardous. From a scientific
standpoint, the environmental and
health benefits of Bt plants have been
well documented. However, these
benefits often get lost in the bigger
discussion on biotechnology, and this
presents a serious dilemma in a demo-
cratic society.I strongly believe that scientists have an
obligation to make their voices heard on
important issues such as genetically
engineered plants for pest management,
but we must do so in a responsible
manner. Isn’t it our obligation to help
inform the public dialogue on these
issues? Who else is more qualified to
do so?LIFE BOX 12.1. ANTHONY SHELTON 307