Science & the Public: Bt: The lesson not learned The more things change, the more they stay the same, as a Dec. 29 Associated Press report on genetically engineered corn notes. Like déjà vu, this news story on emerging resistance to Bt toxin — a fabulously effective and popular insecticide to protect corn — brings to mind articles I encountered over the weekend while flipping through historic issues of Science News. More than a half-century ago, our magazine chronicled, real time, the emergence of resistance to DDT, the golden child of pest controllers worldwide. Now much the same thing is happening again with Bt, its contemporary agricultural counterpart. Will we never learn?