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Genetically modified crops - February issue

David Brear dbrear at wharfe.demon.co.uk
Sun Feb 7 15:27:57 EST 1999


In article <36BDCEB9.2CF6C53C at mr.net>, David Kendra
<dkendra at mr.net> writes
>Martin Tom Brown wrote:
>
>> Odd. I thought the main advantage was that you could spray the whole
>> field and kill the weeds without damage to the Roundup ready crop.
>> Under most circumstances wholesale spraying of the entire field
>> will use more active chemical than spot weeding. It will however
>> use much less *labour* to apply it and so will be cheaper to do.
>
>Farmers using GM plants with Roundup resistance is is simply substituting 
>Roundup for
>another herbicide that would have been broadcast over the entire field.  Depending 
>on
>the herbicide used, the grower may need to spot treat with  Roundup as you 
>suggest.
>Additionally,  growers can often apply lower concentrations of Roundup since 
>they are
>applying the herbicide earlier in the season.  Spot application is typically made
>when plants are larger and more difficult to kill with a herbidice.  All in all, the
>farmer uses less herbicide, and makes fewer passes over his/her fields.  That is 
>why
>herbicide GM technology has taken off so rapidly, not because a farmer can use 
>MORE
>chemical.
>
>> I am inclined to agree that Glyphosate is relatively OK, but
>
>> crosses of GM rape with native weeds show signs of producing
>> some Roundup ready super weeds. That would not be very helpful.
>
>Was the herbicde resistant wild rape produced by well controlled crosses in the 
>lab
>(I consider glasshouse and field plots a "lab" environment) or where they detected 
>in
>weeds near M rape?  Under artificial conditions, breeders can make "WAC's" (wild 
>ass
>crosses) that would never survive or occur naturally in nature.
>
>Best regards,
>Dave Kendra
>
Dave,

Not being a scientist, I have been following this thread with more interest
than involvement.

However, I think you may be wrong about the intended use of the new
technology, as advertised, at least. In one of Monsanto's recent publicity
coups, they arranged for the press to inspect crops growing at a trial site
and said the advantage was that they could be allowed to grow for longer
than with conventional control techniques, thus allowing insect
populations to flourish. I quote from the Financial Times, 25 August 1998
(not quite Nature, I know):

"Many of Roundup's environmental advantages stem from the fact that,
because it is such an effective herbicide, weeds can be allowed to grow
much bigger than normal and sprayed just before they begin to compete
with the crop. The Cambridgeshire trials show that, instead of the bare
earth normally found around conventionally treated beet plants, there is a
mulch of dead and dying weeds, which provides a better environment for
insects while conserving water and reducing soil erosion. "

I am personally against GM crops but it seems that on this simple basis at
least, the new tech may be helpful.

David Brear
dbrear at wharfe.demon.co.uk

The Wildflower Page
http://www.wharfe.demon.co.uk/wildflwr.htm

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