----- Original Message -----
From: "sbissell" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Tuesday, July 29, 2003 10:36 AM
Subject: Re: Genetic Engineering
> Just a note. One of the promoted reasons for GM crops is that they require
> *less* pesticides. Not saying for myself that this is good or bad, just an
> observation.
> Steven
Ironically, though, it has been exposed that GM crops increase pesticide
use. I mentioned this earlier regardin Bt corn. Due to the inability of the
farmer or ag technician determining the extent of the corn borer early in
the season, it is customary to plant Bt corn as a cautionary measure,
regardless of whether the actual incidence is 5% or more in the corn. Thus
what happens is the biopesticide is release continually into the soil,
killing other species of insects, and some beneficial insectorous insects.
Later organophosphates are used to control the insects which are 'released'
from the predators. So there - I argue - no net decrease in the use of
pesticides, overall.
One thing I should mention is that some insects are benefitted by pesticides
including detrivores, those insects which rely on dead vegetation may
increase after pesticide useage where there is dead vegetation. Some of
these are called 'comminuters' and fragment and comminute vegetation. The
effect though is relatively short term. Thus, all things considered,
irrigation, soil amendments, agrichemicals on balance increase biomass,
thus potentially there is more 'habitat' for certain insects. Separating out
though the effects of the pesticides and the GM there is no reason to
believe that pesticides and GM crops in general have any advantage (in terms
of growth and yield) over non-GM and pesticide free agriculture; the GM crop
though has the potential to reduce inputs such as Roundup Ready soybeans
which are planted, sprayed and fertilized all at once in the spring (cf.
conservation tillage). In making a contrast what it boils down to is that in
organic farming there are virtually no subsidies, and the labour inputs are
often greater, and the demand for organic, non-GM crops is greater,
resulting in higher prices. One one side of the ledger is the GM crop which
requires lower labour and on the other is the organic crop which requires
greater labout. For instance, organic beef. If the demand for organic beef
is such that the consumer is welling to pay a small premium for the safety
(all organic beef is fed a vegetatarian diet, the fodder or grain is
organic, and there is no use of biochemicals (eg. hormones, et cetera), then
it would appear that many levels of safety are covered off (virus free,
lower releases and transfers of animal wastes, leaching, and so on).
However, over the long term the potential for soil, water, and wildlife
impacts associated with intensive GM crop is expected to be significant,
even after a period of 3 years of continuous use. These costs accumulate and
it is the owner of the land which bears the cost, society though also pays
indirectly for the costs (ecological and social too).
jmf
>
> >===== Original Message From "Discussion forum for environmental ethics."
> <[log in to unmask]> =====
> >----- Original Message -----
> >From: "sbissell" <[log in to unmask]>
> >To: <[log in to unmask]>
> >Sent: Monday, July 28, 2003 1:45 PM
> >Subject: Re: Genetic Engineering
> >
> >
> >> John wrote "Be difficult to find a population of shrews in a GM Canola
> >field,
> >> dare say."
> >>
> >> Steven here; Why is that John? Do shrews live in non-GM Canola? Just
> >asking,
> >> don't really know. If they do, no reason why they couldn't live in GM
> >Canola.
> >> sb
> >>
> >
> >Actually I researched this topic thoroughly over a decade ago. There were
a
> >great number of field studies completed in the UK but Perceival Potts.
The
> >research was largely consistent, and appears to demonstrate that modern
> >agriculture was having an devastating effect on song bird and game bird
> >populations. The hypothesis was presented that pesticide use, removal of
> >weeds, and removal of fence rows was causing serious declines thorough
out
> >the UK where modern agriculture was being carried out. The solution was
> >suggested to stop using pesticides, to retain more fence rows (natural
> >vegetation and habitat).
> >
> >I think Steven is 'on the money' regarding shrews in plantations. The use
of
> >Roundup Resistent canola (if there is really a use here) is pertinent
since
> >the Roundup would be used as a 'post emergent' herbicide and be very
> >effective in removing weeds (which are specific food sources for insects
> >such as the lepidoptera, circulionidae, et cetera). Broad spectrum
> >herbicides have been extensively studied in forestry applications as to
the
> >impacts on insects, and other species, and the general consensus is that
the
> >'simply' species diversity, and some cases remove species even after one
> >application. There are hundreds of studies globally on the impacts of
> >herbicides in forestry plantations. But at the same time there are few
> >comparisons with alternative methods of control. '
> >
> >Now I would be taking a 'cautionary approach' to the application and use
of
> >GM forestry crop such as Roundup resistent poplar, for the same reasons.
> >There are known hazards with the pesticides, and there are unknown or
> >potential hazards with the GM poplar, one being that they are designed
not
> >to produce catkins. Which means that many species will be unable to feed
> >themselves, afterall black bears, cubs, use cottonwood catkins in the
> >spring. The risk associate with the GM cottonwood is so obvious that GM
> >engineers have devised a strain which cannot produce the pollen and seed
> >which would hybridize with the native cottonwood. The other thing is that
> >the cottonwood potentially could put on more wood because less energy is
> >used for reproducing seed.
> >
> >It seems like even the engineers of GM plants also are worried about the
> >ecological impacts, and thus have taken a cautionary approach. I
personally
> >do not want cottonwood in my valley or any poplars which cannot produce
> >seeds because of their vital importance to wildlife. Cottonwood are
common,
> >or predominant in all the low elevation valley bottoms whether near the
> >desert or in the coastal rainforest. They are just too important to
tamper
> >with. How to remove the offending genes after they spread many kilometers
in
> >the wind and water. Spells disaster.
> >
> >To make matters worse, the GM cottonwood may even produce seeds and
pollen.
> >
> >Also:
> >
> >Shrews are insectivores. Thus they would be consuming up to their own
weight
> >in insects each day. Shrews would have to have a lot of insects, and if
the
> >Canola was treated with herbicides and insecticides and was a monoculture
> >(GM or not) there would not be sufficient prey species for the shrew. The
> >issue appears to be one of 'competitive exclusion': humans devise a crop
> >which is depauperzed of insects by using insecticides. Now if 99% of the
> >prairie is now cultivated in similar fashion, then the shrew populations
> >would be non-existent or very small. Prairie gophers are extinct from
these
> >areas.
> >
> >jf
>
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