Bt - more

[Pierre Zagatti]

Bruce Walsh wrote:

> ...
> Given that only larvae are potentially effected, and only LEP larvae (not
> other insects), its clear that BT corn is FAR better than current
> treatment for other insects and associated members of the foodchain.
>
> It was be very sad indeed if a product that REDUCED the loss of leps due
> to corn farming was kept off the market in favor of approaches that
> (potentially) do far more damage.
> ...

Very sad would be the loss of a useful and efficient method (use
of classical Bt spray in an Integrated Pest Management strategy)
for a totally inefficient method (selection of resistant
pest strains by a permanent exposure to a toxin producing plant).

It seems that there is a huge misunderstanding about what is a pest.
Among thousands of Lepidoptera species, only a few are pests.
They are species that have the ability to adapt quickly to environmental
changes to exploit the biomass of a monospecific field crop. In other
words, they have the genetic potential to detoxify Bt (or other) toxin
in 2 or 3 generations whereas other species won't succeed
in 100 generations.
In my lab, scientists are working for years on insect resistance
to insecticides. When they want to build a new strain for
a pest resisting to an insecticide, either they collect specimens
in a heaved treated field, or they apply permanently the insecticide
to their wild strain in the laboratory. Now the latter strategy will
be applied at a large scale in Bt corn fields...


--
Pierre ZAGATTI
INRA Unite de Phytopharmacie et Mediateurs Chimiques
78026 Versailles Cedex
FRANCE
Tel: (33) 1 30 83 31 18
e-mail zagatti at versailles.inra.fr
http://www.jouy.inra.fr/papillon/