Ecol. aspects of transgenic crops summary (fwd)

Paul Cherubini cherubini at
Wed Apr 19 11:33:41 EDT 2000

Jim Kruse wrote in regard to the executive
summary of the workshop on ecological impacts of transgenic
crops held on UC Berkeley Campus March 2-4, 2000:

> unanticipated effects on non-target herbivorous insects (i.e. monarch
> butterflies) through deposition of transgenic pollen on foliage of
> surrounding wild vegetation;

Jim, I am unaware of any study documenting that even one unmanipulated
monarch caterpillar feeding on an unmanipulated milkweed plant growing
as a weed within or near a Bt corn field ever died from exposure to 
Bt corn pollen.

Moreover, as the percentage of the Midwest corn crop planted in Bt corn
rose from roughly  5% in 1997 to 30% in 1999, the size of the 
overwintering population of monarch butterflies in Mexico has actually

(total monarch coverage at  5 major overwintering sites in hectares)

Winter of:                     approx % of Midwest corn planted in Bt corn

1997-98:  3.18 hectares                    5%
1998-99:  5.21 hectares                  20%
1999-00:  5.97 hectares                  30%

Paul Cherubini, Placerville, California

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