WEST LAFAYETTE – Today’s farms are constantly innovating, relying on cutting edge technology and bioengineering to control pests. The U.S. Environmental Protection Agency, however, has struggled to keep pace, becoming rooted in a game of regulatory “whack-a-mole”: When one chemical pesticide withers, another one sprouts up.
“We don’t regulate pesticides until their risk profiles are clear and fully developed,” said Purdue University historian Frederick Davis, author of “Banned: A History of Pesticides and the Science of Toxicology.”
The cycle began in the 1940s with DDT and, later, organophosphate insecticides, both of which were exposed as harmful in Rachel Carson’s 1962 book “Silent Spring,” which sparked the modern environmental movement, Davis said.
“There’s a constant shift from a pesticide like DDT, where the risk profile was well established through the 1950s and 1960s,” he said. “Even though organophosphate insecticides were shown to be highly toxic, they became dominant from the 1970s to the early 2000s. And when their registrations were canceled, farmers turned to neonicotinoids.”
Neonicotinoids are sprayed on a variety of seeds and cause plant tissues to become toxic to pest insects, said Davis, the R. Mark Lubbers Chair in the History of Science in Purdue’s College of Liberal Arts. Coming full circle, the chemical builds up in the environment, or bioaccumulates, similar to DDT, though more gradually.
“Neonicotinoids are a class of insecticides that is extremely effective against target organisms and has very low toxicity to most mammals, including humans,” he said, “but they’ve been linked in scientific reports to declines in grassland bird species and honeybees.”
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