Bt Crops - Modern Application of Artificial Selection - Reading (6-8 Grade)

Battling the effects of the European corn borer caterpillar has been an ongoing challenge for farmers that grow corn. It is estimated that it costs growers more than a billion dollars every year in pesticides and lost crops. When scientists discovered that the proteins in a very common soil bacterium, called Bacillus thuringiensis (Bt), were toxic to the corn borer, they helped develop the first bio-pesticide. This was sprayed on corn and other crops. It was considered safer than other pesticides because it only killed a small number of targeted pests. The Bt insecticide, when ingested by the caterpillar, binds to the wall of the gut and breaks it down, killing the insects.

Then in 1995, scientists were able to move some of the genes from Bt into the corn plant itself. This became genetically engineered (GE) Bt corn (and other crops). Bt crops fight off not just the European corn borer, but other costly pests as well (e.g. rootworm, corn earworm, tobacco budworm, and bollworm). Bt was thought to be such a good match for a GE pesticide because testing showed that it only affects insects and not mammals, fish or birds.

Because of the concern over the real health affects associated with synthetic pesticides, scientists hoped that the adoption of Bt crops would decrease the overall use of pesticides. This seems to have borne out, as the USDA released statistics that between 1995 - 2010, the amount of pesticide used on corn decreased 99%. Studies are still ongoing to assess any downside to theuse of Bt crops. A 2015 publication by the National
Institute of Health (NIH) supports the safety and benefit of using Bt crops. To date 81% of corn grown in the U.S. have Bt genes. Bt crops may be the oldest and most successful genetically modified (GM) food in U.S. history.

Another online reference (off site) from Harvard University