University reports that the Monarch caterpillars can be killed by this
Bt toxin containing corn pollen. He basically placed Bt containing corn
pollen on milkweed plants in his lab and found up to 44 percent of the
caterpillars had died. This was a much higher mortality rate than the caterpillars
fed milkweed plants with Bt free corn pollen on them. The Bt corn pollen
fed surviving caterpillars were also much smaller than caterpillars fed
Bt free corn pollen.
This is definitely a problem. However, a few things must be kept in
mind before throwing out this means of controlling corn pests. Losey did
these experiments in his laboratory. Did his experiments closely mimic
real life corn field conditions? Actual in field observations of milkweed
plants demonstrate very little corn pollen on the leaves. When Laura Hansen
and John Obrycki of Iowa State University fed Monarch caterpillars milkweed
leaves from the corn field's edge they only got a 19 percent death rate
of the caterpillars. Pioneer Hi-Bred International of Des Moines Iowa,
a Bt corn producer, says that the peak feeding time for these Monarch caterpillars
occurs before the corn plants start shedding their pollen. Still other
people say that spraying pesticides all over the fields kills all the insects
in the area for sure. If wind causes the pesticide spray to contaminate
surrounding areas there is much more potential loss of insect life.
The moral of the story. Whenever you try to solve one problem you can
potentially cause other problems and everything in life has a cost benefit
ratio. What are the costs compared to the benefits? Do the costs outweigh
the benefits? In this particular case a potential cost of this new Bt containing
corn crop has been demonstrated. In my opinion, I don't believe the data
are convincing enough to warrant stopping the production of Bt containing
corn crops. More in-field studies need to be done to assess the costs of
this product. Let's not throw the baby out with the bath water until a little
more is known.
Knowledge is Power. For more power click below.
The
Scientist article on this subject.
Take Care and Think Microbiologically!
