What are the major environmental risks from the growing of GE crops?
GE crops might harm the environment in several ways. One way is for the crop to produce substances that kill beneficial organisms above or below ground. Those toxic effects would be limited primarily to the crop fields, but since crops are a major land use, the harm could be considerable. Initial evidence suggested that Monarch butterflies might be harmed by certain Bt corn varieties, but additional and more extensive experiments showed that harm to be unlikely. Another way GE crops could harm the environment is if they grow where they are not wanted. While most cultivated crops do not survive beyond well-tended fields, seeds from one year’s crop that are not harvested may grow the following year, when a different crop may be planted. Those “volunteer” plants may be undesirable in the new crop. If the “volunteer” is an herbicide-resistant variety, there may be fewer or less desirable choices to control it. That has occurred with some herbicide-resistant canola in Canada, where control
