In this chapter’s introduction, you learned two main points of view regarding the use of GMO crops. Using the Internet, learn about a strain of corn known as Bt corn (Bacillus thuringiensis). Find out if the proper tests have been done, as determined by USDA, EPA, and FDA, to ensure that Bt corn does not harm beneficial insects and the public can consume it safely without worrying about side effects.

Question

What will be an ideal response?

Answer 1

The ethical process can be used in answering this question, and it
should be emphasized to students that all factors need to be considered
and weighed in proportion. USDA, EPA, FDA, and the CDC were involved in
mandating testing by the company and contracting testing the agencies felt
needed to be done. Below is a historical summary of testing the Bt protein.
Some of the testing was done as a response to concerns raised by the media
and the public after the product was released to market. More information
can be found through Web searching:
• Why Bt corn was developed: The reason Bt corn was developed
was the amount of damage done by the corn borer globally. This
insect was only partially controlled using chemical insecticides and
using insecticides often damaged nontarget insects. Since Bt corn
was introduced, use of pesticides recommended for European corn
borer control decreased from six million to slightly over four million
acre treatments in 1999, a drop of about one-third, according to the
Environmental Protection Agency.
• Testing for Human Consumption: Testing was done to determine if
the Bt protein was safe to eat or could cause an allergic response in
people. The fi rst Bt corn variety contained a Bt protein shown to be
artifi cially digestible so was thought not to be a threat to humans
when eaten. However the second variety, Starlink, had a diff erent
Bt protein that did not break down as well in the artifi cial digestion
tests, so it was banned from human consumption. It was supposed
to be used for animal consumption or in the production of biofuel.
However, it did make its way into human food. Tests were run by the
company that sells it, Adventis, which felt it showed the Bt variety
broke down with heating. Others felt these tests were inclusive.
Fifty-one people claimed to have an allergic reaction but research by
the CDC showed those claims to be false.
• Testing to ensure Bt corn was safe for the environment: Scientists
were worried that Bt corn would kill monarch caterpillars as monarch
butterfl ies lay their eggs on milkweed plants in and around corn
fi elds. It was thought, that the pollen from corn plants, would fall on
the milkweed leaves killing the caterpillars. A preliminary study done
at Cornell University showed monarch caterpillars might be harmed
by eating pollen from Bt corn plants. Other scientists questioned
the experiments’ design that produced this conclusion. So, a group
of scientists, including ones who studied the caterpillar in the fi eld,
met and compared notes. In the laboratory experiment, corn anthers
containing pollen from Bt plants were ground up and the mixture
was coated over the leaves that the caterpillars were eating. However,
this is not what occurs in nature. Pollen from corn plants may fall on
milkweed leaves but not in the high concentration was used in the
laboratory experiment nor does ground up anthers contaminate
milkweed leaves. When the ground up anthers were removed from
the mixture, it was no longer toxic to the caterpillars. Studies are being
conducted to determine if the caterpillars are killed with prolonged
exposure to the pollen.
• Keeping it in Perspective: The major reasons this species is decreasing
in numbers has been shown to be the following: destruction of the
monarch’s habitat such as the mowing of highway rights-of-way,
ditches, and pastures; collisions with cars and trucks; insecticides
used before Bt corn existed; and being eaten by other insects. All
of the factors, included Bt pollen, should be weighed in the correct
proportion as to what kills these butterfl ies and their caterpillars.