Some crops that were genetically modified to be resistant to insect pests are losing that power, NPR reports.
It notes US farmers began using Bt crops in the late 1990s. The crops were genetically modified to include proteins from the soil bacterium Bacillus thuringiensis that are poisonous to the larval stages of a number of insect pests.
However, it reports that some pests are now becoming resistant to Bt crops — a scenario scientists worried about and tried to avoid by asking the US Environmental Protection Agency to limit the portion of land that could be used to grow Bt crops and require farmers to also grow non-Bt crops. While, as NPR reports, the EPA adopted the measure, there were disagreements over how much land had to be set aside for non-Bt crops.
It adds that scientists are again calling for new rules, especially ones that protect versions that came on the market later. Julie Peterson, an entomologist at the University of Nebraska, tells NPR that, without any rule changes, all Bt genes on the market could stop working within a decade.