Might GM crops add another stressor to freshwaters?

It’ll be interesting to see the details of a new Government report coming out tomorrow on the need for GM crops, reported here.

I’ll be wondering about one very specific area: the possible impact on freshwater. In the United States there’s widespread planting of maize engineered to produce an insecticidal protein originally derived from the bacterium Bacillus thuringiensis. The maize should in theory protect itself from the pest.

There’s now clear evidence that the protein (i.e. the insecticide) is getting into streams on a fairly large scale in bits of dead maize – leaves, cobs, husks, stalks that get into the streams near the maize field.

But is that a problem?

In lab studies, the maize with added insecticide can reduce the growth rate of caddis, though it doesn’t actually kill them. This isn’t too surprising because caddis are quite closely related to moths and butterflies which the Bacillus thuringiensis protein will kill. The main maize pest that the GM engineering is targeting is the European Corn Borer – which is a moth.

But in the field, there’s no effect discernible effect of the engineered maize pesticide.

Ironically, this is could be because, in the cropland environment, the animals that might be sensitive to the GM pesticides have already been eliminated by other forms of environmental stress: nutrients, pesticides, channelization and altered flow.

This is the only published information on the subject so far: but it’s worth watching. It may add yet another stress to our already troubled waters.

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One Response to “Might GM crops add another stressor to freshwaters?”

  1. Tweets that mention GM crops could add another stressor to freshwaters « The Garden Pond Blog -- Topsy.com Says:

    […] This post was mentioned on Twitter by Jo Cartmell and Lucy Greenfield, Jeremy Biggs. Jeremy Biggs said: Might GM crops add another stressor to freshwaters? http://t.co/zuFyPqy […]

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