From 2008 to 2011 several research projects will once again be investigating
the environmental impacts of genetically modified Bt maize.
A new trial field was prepared for this purpose at the start of the 2008
growing season. This series of research projects is being funded by the
German Ministry of Education and Research (BMBF) as part of its biological
safety research programme.

The genetically modified Bt maize being tested in this trial series contains
several introduced genes, called ?stacked genes?. Two different Bt genes
make it resistant to its main chewing pests, the European corn borer and the
Western corn rootworm . The corn borer caterpillars chew through the maize
stems, while the larvae of the Western corn rootworm attack the roots of the
maize plants. The two previous series of research projects tested Bt maize
that was resistant to just one of the two pests. The maize being tested now
also contains a herbicide-resistance gene.

Trial design
At the start of the biological safety research into Bt maize, Bt maize was
compared only with the isogenic variety, i.e. the conventional parent
variety. In this trial series, two more conventional varieties are being
grown in addition to the isogenic variety. It is suspected that differences
in the incidence and abundance of individual insect species may be greater
between different conventional varieties than between Bt maize and the
isogenic variety.

There are also plans for plots on which the isogenic variety will be treated
with a soil insecticide. In previous experiments it was found that an
insecticide treatment had much more serious impacts on the living organisms
in the field than the genetic modification.

Each of the maize variants is being grown on eight plots. They are
distributed according to a ?randomised plot design?. This means that the
different varieties are distributed at random, but respecting certain
conditions: plots of the same variety must not be placed immediately
adjacent to one another, and there must be a similar number of plots of each
variety around the edge of the field and in the middle.

Under the microscope: ground beetles, bees and butterflies As in previous
years, the researchers are focusing primarily on the small living organisms
in the maize field. RWTH Aachen University is investigating possible impacts
of Bt maize on the broad spectrum of insects and spiders found in the field.
One of the things they will be researching is to what extent butterflies
living at the edge of the field come into contact with Bt maize pollen.

A project being conducted by the Bavarian State Research Center for
Agriculture is focusing specifically on ground beetles and spiders.

This series of research projects will also be looking at bees for the first
time. The University of Bayreuth is investigating whether bees tolerate Bt
maize pollen less well than conventional pollen.
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