Monday, August 28, 2000
Yet another report has raised the prospect that pollen from
Bt corn is toxic to Monarch butterflies. However, as the results were based
on the ingestion of pollen in the laboratory, rather than under field conditions,
the new results are likely to do little to change opinions on either side of
Researchers from Iowa State University
published, in Oecologia, that milkweed plants grown within 3 meters of fields
planted with Bt corn - YieldGard or KnockOut varieties from Novartis Seeds Inc.
(Golden Valley, Minn.) - carried an average of 135 pollen grains/cm2.
In subsequent laboratory tests of leaf disks carrying that amount of pollen,
37-70 percent mortality of Monarch butterfly larvae was observed at 120 hours
following a 48-hour exposure.