The other "other" side

Paul Cherubini cherubini at
Thu Aug 3 05:28:59 EDT 2000

John Shuey wrote:
> One thing to note about Bt corn.  Many farmers in the Midwest are worried
> that because corn apparently has a tendency to cross with Johnson grass
> (strong evidence of genetic exchange has been established between these two
> species), that Bt genes will become the norm in this major economically
> negative weed.  Farmers aren't happy about the prospect of an insect
> resistant ag weed developing in the Midwest.

Bt corn crossing with johnsongrass? Wow, this is news. Do you
have a reference, John?

I have heard of cultivated grain sorghum (Sorghum bicolor) hybridizing
under field condition with johnsongrass (Sorghum halepense),
but not corn and johnsongrass.

In any case, the only insect that Bt corn provides good control of
is the European Corn Borer Moth. Other moth pests of corn are not
well controlled. Even if they were and a Bt johnsongrass was 
accidentally created, what would be the consequences?. I have never
heard of a case where the feeding damage of a lep caterpillar was
extensive enough to impact the abundance of a widespread
exotic, invasive crop weed like johnsongrass.
Have you heard of such a phenomenon?

Paul Cherubini

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