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Re: GM crops leak toxins, archive 2296



Dear Rick Roush ,
you wrote :

>>THE TIMES THURSDAY DECEMBER 2 1999
>>
>>GM crop toxin is leaking into the soil
>>
>>BV NICK NUTTALL  ENVIRONMENT CORRESPONDENT
>>
>>SOME genetically modified crops are leaking powerful toxins from
>>their roots into the soil, scientists have found....
>
>Still more sensationalist reporting.  What the authors actually said in the
>conclusion of their paper:
>
>"We have no indication of how soil communities might be affected by Bt toxin
>in root exudates in the field. Bt toxin in the rhizosphere might improve
>the control of insect pests, or it might promote the selection of
>toxin-resistant target insects.... Further investigations will be necessary
>to shed light on what might happen underground."
>
>In sum, all they know is that Bt toxin gets into the soil. Have you seen
>many caterpillars eating soil?

I disagree with you : the conclusion you quote envisages
promotion of selection. So there should be a pression of selection.

A fortiori there must be an effect depicted in their article.

Yet I acknowledge that I cannot understand how Bt can be efficient (I mean
in the same way as it is to lepidopters !) toward worms.

Yet (again!) if, as you quote, Bt can have efect on famrers, it must
be that Bt has other effects than linked to the basicity of the gut of
lepidopters (by the way what is the order of basicity needed to have Bt 
transformed into the insect-killer molecul(s) ?).


>>It will raise fears among some scientists, regulators and
>>environmental groups that beneficial soil organisms might be killed
>>and that insects living in the soil might become resistant to the
>>poisons.
>
>Any specific examples that can be given?
>

Any example of organism submitted to a molecule toxic WILL develop
resistance. The only question is when.
>
>
>>Other research found that lacewings that had fed on corn borers reared
>>on BT corn had also died, raising concerns that such crops are harming
>>more than just pests.
>
>Only among some people, since the corn borers live inside the plant and the
>lacewings eat eggs and aphids on the outside.
>
Did one check lacewings fed with the eggs and aphids of corn borers (fed with Bt 
corn) ?

Yours
HLM