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Crop loss due to pests is a major challenge for agriculture and pesticides are expensive.
However, with the advent of genetic engineering, highly targeted strategies for pest control have become available in the form of transgenic plants with insecticidal traits. Specifically, these crops were developed by moving some of the genes from the bacterium Bacillus thuringiensis (Bt) into corn and cotton.
Since the 1990s, corn and cotton with Bt genes have become the predominant varieties planted in North America. Yet despite their long-term usage and widespread presence in the U.S. food supply, debate and misinformation about the safety of Bt and other genetically modified (GM) crops persists.
What makes Bt such a great candidate for GM applications is that while its toxins are highly effective against insects, they have been shown to be safe for consumption by mammals.
What are the wider environmental impacts of Bt crops?
Bt crops use less pesticide. In 2001, Bt adopters were using approximately 36% less insecticide than non-adopters. And the use of pesticides, on both Bt and non-Bt crops, has dramatically decreased overall. Some studies have found evidence that the use of Bt corn and cotton is associated with a broad suppression of the overall population of damaging pests.
There have been no documented cases of off-target effects of Bt crops in the field. In the late 1990s, it was reported that high levels of pollen from Bt crops were toxic to Monarch butterfly larvae. But it was later shown that the conditions under which this toxicity was observed do not exist in real-world applications of Bt. The more localized action of GM Bt crops appears by all accounts to have less of an ecological impact than non-Bt methods.
Editor’s Note: This post is part of a series on GMOs in a special edition of the online magazine “Signal to Noise”, produced by Science in the News. You can read the entire series here: Signal to Noise Special Edition: GMOs and Our Food
Read full, original post: Insecticidal Plants: The Tech and Safety of GM Bt Crops