Bt corn is a genetically modified form of corn. It has been genetically modified to express the toxins found in Bt. The new Corn plant has toxins throughout the entire outer layer of the plant. These toxins although lethal to many insects pose virtually no risk to humans. Unlike conventional pesticides, Bt is very selective and only attacks a certain small group of insects. The strain that is found in Bt corn is most effective at controlling the European Corn Borer, which is the largest pest of Corn in the US.

So what does Bt do in Corn crops? It acts as a protection against insects, mostly caterpillar and moth larvae. Insects like the Diamondback Moth and the European Corn Borer cause millions of dollars worth of damage every year. It costs farmers small fortunes to spray their fields with insecticide to keep the wee beasties off the crops (about $1 billion per year in the United States), and the large amounts of synthetic pesticides they use are extremely harmful to the environment.

Because of the way the bacterium and Cry toxin work, they are extremely specific. Only certain insects will be even remotely affected by Bt, and there are no records of mammals or birds becoming sick or ill from Bt. North American consumers have been consuming Bt corn corn for the last few decades, to no ill effect. Aside from the general ethical questions surrounding genetically modified crops in general, Bt has been a relatively moot issue for many years.

Stock Rot in Bt and non-Bt crops.

Courtesy of Integrated Plant Management

Strangely enough, breeds of corn that have been modified with Bt also seem to be more resistant to certain diseases, like Stalk Rot, a fungal infection which can ruin corn crops. Many plant-feeding insects carry fungal diseases, mycotoxins, which can cause plenty of damage, and often threaten human and animal health. When these insects are killed off, and feeding less on the Bt corn, the fungal infections spread slower and deal less damage. Thus, we are seeing some positive side effects from the use of Bt corn.

Mostly harmless, one would assume. Bt corn was being used, widespread, across Canada, the United States, and Europe, for many years, before there was any problem with the technique. However, despite the ultra-narrow spectrum of insects affected by the toxin, there is one organism that appears to be at risk from the Bt corn. Read on to discover more.