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7-Misc: Canadian scientists concerned about GM risks being largely ignored



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TITLE:  The tip of the iceberg: genetically altered corn is bug
        free but it's killing the monarch butterfly
SOURCE: The Kitchener-Waterloo Record, Canada
        sent by AGNET, Canada
DATE:   July 10, 1999

----------------- archive: http://www.gene.ch/ ------------------


THE TIP OF THE ICEBERG; GENETICALLY ALTERED CORN IS BUG-FREE BUT
IT'S KILLING THE MONARCH BUTTERFLY

Peter Kevan of the dept. of environmental biology at the
University of Guelph writes in this op-ed piece that in Ontario
this year, some 255,000 hectares (half a million acres), or about
one-third of all fields in which corn grown for livestock feed,
is planted with transgenic hybrids. The corn has been genetically
altered so that it includes the genes from a bacterium, Bacillus
thuringiensis (or Bt) that produces a poison deadly to moths and
butterflies (the insect Order, Lepidoptera). The corn plants with
Bt genes make the bacterial poison, in effect making the entire
plant into a pesticide. The poison protects the corn plants
against the ravages of, say, corn ear worms or corn borers as
serious pests of corn. Kevan says that the benefits to
agriculture and crop protection are in crop protection without
application of sprayed pesticides. But, are there risks which
have been overlooked? Is there a downside to the technological
benefit?

Kevan adds that a recent article by a small team of scientists at
Cornell University and published in Nature describes potentially
harmful effects of pollen from transgenic corn plants that
produce Bt poison. When this pollen was placed on milkweed, the
sole food for monarch caterpillars, and so fed to the
caterpillars, they grew more slowly than normal, fed more slowly,
and were more likely to die than are caterpillars fed on the same
diet without this pollen, or with just normal corn pollen. The
natural diet of monarch caterpillars here is field milkweed. The
large green caterpillars are a familiar site on milkweed, as are
the bejewelled chrysalids hanging beneath the leaves. Field
milkweed (along with other species of milkweed, some of which are
rare and endangered) is designated a noxious weed in Ontario. It
is common around corn fields.

The pollen of corn plants is dispersed by the wind, and, even
though quite large and heavy, can blow well beyond the borders of
corn fields. Kevan says that Bt-corn pollen poisonous to monarch
caterpillars will be blown onto milkweed plants this summer and
there, presumably, it will adversely affect populations of the
monarch butterfly. At present, it is not possible to estimate
what the effects of reducing populations of monarch butterflies
will be. In fact, it is not even known that a reduction in
populations of monarch butterflies would have any major
environmental impact. Kevan says that a small number of concerned
scientists in Ontario, other parts of Canada and around the
globe, have been calling for environmental and societal risk
assessments of the release of transgenic crops into the
agricultural landscape. By and large, he says, their voices have
been ignored or, at best, their concerns belittled.

Kevan says the scenario presented by the study on monarch
caterpillars and pollen from Bt- corn is the tip of a potentially
immense iceberg. The risk from Bt-corn can clearly extend beyond
the borders of corn fields and agricultural land. The poison
escapes from the plant and, in all likelihood, can adversely and
directly affect a variety of other non-target insects in the
neighbourhood of corn fields. He goes on to say that the need for
environmental risk assessment is greater for transgenic
pesticides in crop plants than it is for the usual chemical
pesticides because the effects may spread faster and further
beyond the treated areas. Yet, Kevan maintains, the environmental
risks remain unstudied. The benefits expected by way of pest
control in agriculture and forestry from Bt transgenic technology
must be weighed against potential environmental hazards.

Industry promotes the technology, but funds little, if any, risk
assessment, particularly in Canada. Scientific laboratories at
both federal and provincial levels, says kevan, seem reluctant to
support research on risks, but have major programs in transgenic
technology. University researchers concerned with the risks are,
he says, informed that public funding is contingent on matching
money from industry that somehow demonstrates the societal value
of the much-needed work. 



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