Monarch Butterflies and Bacterial Toxins

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!

Go To Page: 1 2

Articles in this Topic    Discussions in this Topic