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Disease
and Pest Control
Pesticides and alternatives
 There
is a heavy mandate in the U.S. to develop alternatives
to chemical pesticides for controlling agricultural pests.
Studies have shown chemical pesticides can cause significant
health risks to humans, contaminate water supplies, and
harm non-target life. One solution to this problem involves
genetically enhancing plants to combat pests directly.
Plants can be grown without chemicals and with increased
resistance to disease and pests by using genetic engineering.
Sugar beets, for example, are very susceptible to a variety
of worms, whereas other types of beets are not because
of a protein they naturally produce. Genetic engineers
can take the gene from the worm-resistant beets and insert
it into the DNA of the sugar beet. The engineered sugar
beet is no longer at the mercy of the worm, and the environment
is not harmed.
The following situation is an example of the debate surrounding
the use of genetic engineering in agriculture; like all
choices, it has both positive and negative consequences.
Pros of the Bt Corn Issue
| Some
commercial pesticides have been withdrawn from the
market because of health and environmental risks,
leaving many crops vulnerable to disease and insects.
Several varieties of pests are becoming pesticide-resistant,
rendering the chemicals useless. At Cornell University,
the Bioprocess Development Research project is attempting
to discover new natural products which provide safer
means of pest control using biopesticides (natural
pesticides as opposed to manmade) from fungi and other
plants. |
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A good example of genetic pest control
is the Bt corn plant. One of the most troublesome
pests to corn farmers is a worm called a "corn borer".
As the name implies, this little worm bores into the
husks of corn, weakening and possibly killing the
plant. Even if the plant is not killed, its yield
is reduced because it is weakened so much by the worm
that it cannot use as much energy on growing ears
of corn as it normally would. A second problem associated
with the corn borer worm is that it also transmits
a fungus to the corn when it bores into its husks.
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This fungus produces chemicals called mycotoxins, which
are toxic to humans and animals. Genetic scientists have
found a solution to this troublesome pest, without the
use of chemical pesticides which harm the environment
and humans. Bacillus thuringiensis (Bt) is a common bacterium
that grows in the soil and is harmless to humans and animals.
This bacterium secretes a protein that is toxic to the
corn borer. Scientists inserted the protein producing
gene from the Bt bacterium into the genetic code of corn
plants, and the resulting seeds produce normal corn plants
except that the plant also contains the corn borer killing
protein. When one of the worms bites into the corn plant,
it ingests the protein, and is killed. The protein is
completely harmless to humans, and has been given full
approval by the USDA. Today, nearly 40% of all corn grown
in the United States is produced from genetically engineered
seed.
Cons of the Bt Corn Issue
| However,
a recent study by Cornell researchers proved to be
a large setback for the widespread use of Bt corn,
especially outside the united states in biotechnology
skeptical Europe. The study found that the pollen
from the genetically enhanced plant is toxic to the
larvae of the monarch butterfly. This information
is not new, but it created a public distrust in the
safety of genetically modified foods. The study that
produced these findings has come under attack by many
experts in the biotechnology field as being untrue
to conditions in nature, and many are claiming that
the use of Bt corn actually benefits the Monarch.
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Bt corn proponents argue that in nature, the larvae will
only have a 10 day period in which they may ingest the
pollen from the corn plant, and the pollen may easily
be washed away by rain or dew. Additionally, larvae have
a wide variety of plants to feed on in nature, most of
which will not have the Bt corn pollen on them. Finally,
one must take into consideration the alternatives to Bt
corn. If traditional corn is used, large amounts of chemical
pesticides must be used, which damages a wide variety
of non target life, including the monarch and other species.
They argue that Bt corn is much safer for the monarch
butterfly, and does not effect any other non target life.
Therefore, when all factors are taken into consideration,
Bt corn is actually much safer than current methods of
pest control- safer for humans, and safer for non target
life as well. Still, Greenpeace and other organizations
are calling for the ban of Bt corn, and other genetically
modified foods until their safety to both humans and the
environment may be better proven.
Disease control
One
very important development has been a vaccine for hoof
and mouth disease, which causes sores in the mouths and
hooves of animals, making them weak. It is caused by about
60 related virus types. The first vaccine for hoof and
mouth disease developed using recombinant techniques is
made of a protein called VP3, one of four proteins that
make up the surface of the virus. The protein is spliced
into the genes of E. coli bacteria. This vaccine works
on one of the 60 virus types. Vaccines for hoof and mouth
disease have been developed to combat all the viruses,
but the vaccine's effect is temporary.
    
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