Evolution of Resistance to Plant Incorporated Protectants by Targeted Insect Pests


Agricultural Pesticides:

Intended and unintended effects

The Evolution of Resistance to Plant Incorporated
Protectants by Targeted Insect Pests

Ewartjlng TechnoJogin

Uwe Stolz, Mike Blum, Mark Bagley - Office of Research and Development, National
Exposure Research Laboratory, Ecological Exposure Research Division

Human Health
Effects

Biotechnology May Offer a Solution...

Bt-corn
eliminates the
need for
conventional
pesticides: Good
for Farmers,
Good for Human
Health, Good for
the Environment.

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Unintended
Environmental
Impact

Some genetically modified corn hybrids contain a gene
from the soil bacterium Bacillus thuringiensis (Bt), which
produces an insecticide (known as a plant incorporated protectant) specific
for beetles. Corn varieties containing the Bt gene are known as Bt-corn.

Understanding the
Population Genetics of
Western Corn Rootworm
May Help Delay Onset of
Bt-Resistance

We will develop and use genetic markers
to measure gene flow
between populations
and genetic variation
within populations.

Targeted Insect
Pest

Western Corn
Rootworm (WCR) is
major pest of corn.

80 million acres of
corn planted per year.

Conventional insecticides
applied to 14-18 million
acres per year.

WCR responsible for 1 out of 7 insecticide
applications for all agricultural crops!

...But, the Evolution of Bt-Resistance
is an Environmental Problem

WCR resistance to Bt-toxin would eliminate the benefits of Bt-
corn and require a return to the use of conventional pesticides.

-*¦»	More than 500

f~. How long will it take for
pests to evolve resistance?
It depends on Bt-crop use
and the genetics of the crop
pests.

insect species
have evolved
resistance to a

variety of
insecticides.

Most scientist believe continued use of Bt-crops will result in the
evolution of resistance - they just don't know when.

Measuring gene flow and genetic variation in the WCR will:

1.	Improve accuracy of genetic models currently used to
predict how fast Bt-resistance will evolve.

2.	Help determine how Bt-corn should be grown to ensure
its continued usefulness.

Therefore, our work will help preserve the

environmental, human health, and
economic benefits of Bt-corn for as long
as possible.



Partnering	to Protect	Human

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