Perhaps you could clarify for me what you mean by "this". I'm not
catching the sense of the statement, because my point was ecological
disruption owing to the scale of growing a few GE genotypes. Not
clear how this pertains to communication, adoption, etc.
Your second point pertained to the scale of current (pre-GE) hybrids
and cultivars - fair point. A few, very widely adapted cultivars and
hybrids account for a ridiculous proportion of the hectarage sown to
all the main crops in North America, for the reasons you mentioned.
This has been discussed before on SANET, in the context of the
stability and reliability of yield, and the fact that the homogeneity
of genetics (and the corresponding homogeneity of management to
support that genetics) has actually destabilized yield and reduced
food security. Your point is quite correct, but I'm not sure that
this is a justification for continuing the same trend line. Rather
the opposite, I'd have thought.
The example you reference regarding the sawfly control program is an
interesting one. If I recall from Benbrook's excellent text, Pest
Management at the Crossroads, this was one of the very few examples
of effective, large-scale biocontrol interventions. Almost all of
the rest have been dismal failures, as discussed in his text.
I don't know about the ecological ramifications of
sterile-male release to control sawflies, and having dealt with
malaria-bearing mosquitos myself for part of my life, I for one would
wish them all to disappear permanently. But then again, I'd say the
same thing about snakes - all snakes - which is perhaps more a
reflection of my personal tastes, as well as my ignorance of their
larger role in ecosystem structure and function. More than likely,
something equally or more distasteful would just slither in to fill
the vacated niche(s), because after all, Nature *does* abhor a
vacuum. Maybe that's why the sawfly example is so singular - Nature
really does bat last, and we are overmatched.
My point, which was apparently not well communicated, was that
we are introducing a very large hectarage of a single, completely
novel genotype that is going to have to interact with a large number
of other species. The other species are going to be faced
with the prospect of interacting with the novel genotypes, some
of which are in fact plant pesticides as defined by the EPA, without
the benefit of time to co-evolve defenses. Conventional plant
breeding just moves around existing genes into new combinations.
Genetic engineering creates entirely new constructs, never before
seen by human (or other) eyes, involving entirely new outcomes -
such as the release of active Bt endotoxin on an enormous scale. Is
it so implausible that such a situation, when applied over vast
areas, could lead to a catastrophic outcome?
In many respects, this is not dissimilar from the comparative effects
of synthetic vs. natural endocrine disruptors (ED) on human and other
mammalian physiology. As discussed by Theo Colborn (again, I believe
this has been reviewed before on SANET), plants and herbivores have
evolved together in a kind of dance, where ED apparently evolved as
a tool to deter reproduction/propagation in herbivores. Herbivores
evolved their own counterattack, to at least partially control the
concentration of these compounds in their bloodstream and reduce
their effectiveness. So, it was tit for tat, and ongoing.
But the synthetic ED's (including 40% by weight of the biocides
applied annually in the US) come along and don't play by the same
rules. They are not recognized by the controlling agents in the
bloodstream, and hence, are able to wreck havoc on fetal development
(e.g. dysfunctional immune system, reproductive abnormalities, even
IQ).
As for "walking a fine line" and "agriculture is artificial" - fair
enough. I am quite prepared to support quite a lot of unnatural
stuff, when the need is compelling enough. But this is where GE and
I really part company because I see no compelling reason - unlike the
sawfly and malaria examples - for any of the GE interventions that
have been commercialized to date. Virtually all of the plant
pesticide (e.g. Bt) and herbicide-resistant cultivars are using
genetics to solve a management problem. If we insist on growing
crops (and livestock) in ecologically unsound ways, then Nature will
take us to task and we will have to respond - to "up the ante", yet
again. Each time this happens, it costs more to keep on farming.
Wouldn't it make more sense - economically as well as ecologically -
to use management to avoid these "management-induced" problems in the
first place? Ann
ACLARK@plant.uoguelph.ca
Dr. E. Ann Clark
Associate Professor
Crop Science
University of Guelph
Guelph, ON N1G 2W1
Phone: 519-824-4120 Ext. 2508
FAX: 519 763-8933
http://www.oac.uoguelph.ca/www/CRSC/faculty/eac.htm
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