Opinion: Hearing the Silent Spring 60 years on

In 1962 environmental scientist Rachel Carson published Silent Spring, a bestselling book that asserted that overuse of pesticides was harming the environment and threatening human health.

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Carson did not call for banning DDT, the most widely used pesticide at that time, but she argued for using it and similar products much more selectively and paying attention to their effects on nontargeted species.

Silent Spring is widely viewed as an inspiration for the modern environmental movement. These articles from The Conversation’s archive spotlight ongoing questions about pesticides and their effects.

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Although the chemical industry attacked Silent Spring as anti-science and anti-progress, Carson believed that chemicals had their place in agriculture. She “favoured a restrained use of pesticides, but not a complete elimination, and did not oppose judicious use of manufactured fertilizers,” writes Harvard University sustainability scholar Robert Paarlberg.

This approach put Carson at odds with the fledgling organic movement, which totally rejected synthetic pesticides and fertilizers. Early organic advocates claimed Carson as a supporter nonetheless, but Carson kept them at arm’s length.

“The organic farming movement was suspect in Carson’s eyes because most of its early leaders were not scientists,” Paarlberg observes.

This divergence has echoes today in debates about whether organic production or steady improvements in conventional farming have more potential to feed a growing world population.

Well before Silent Spring was published, a crop-dusting industry developed on the Great Plains in the years after the Second World War to apply newly commercialized pesticides.

“Chemical companies made broad promises about these ‘miracle’ products, with little discussion of risks. But pilots and scientists took a much more cautious approach,” recounts University of Nebraska-Kearney historian David Vail.

As Vail’s research shows, many crop-dusting pilots and university agricultural scientists were well aware of how little they knew about how these new tools actually worked. They attended conferences, debated practices for applying pesticides and organized flight schools that taught agricultural science along with spraying techniques. When Silent Spring was published, many of these practitioners pushed back, arguing that they had developed strategies for managing pesticide risks.

Today aerial spraying is still practiced, but it’s also clear that insects and weeds rapidly evolve resistance to every new generation of pesticides, trapping farmers on what Vail calls “a chemical-pest treadmill.” Carson anticipated this effect in Silent Spring, and called for more research into alternative pest control methods, an approach that has become mainstream today.

Pesticide application techniques have become much more targeted in the 60 years since Silent Spring was published. One prominent example: crop seeds coated with neonicotinoids, the world’s most widely used class of insecticides. Coating the seeds makes it possible to introduce pesticides into the environment at the point where they are needed, without spraying a drop.

But a growing body of research indicates that even though coated seeds are highly targeted, much of their pesticide load washes into streams and lakes.

“Studies show that neonicotinoids are poisoning and killing aquatic invertebrates that are vital food sources for fish, birds and other wildlife,” writes Penn State entomologist John Tooker.

In multiple studies, Tooker and colleagues have found that using coated seeds reduces populations of beneficial insects that prey on crop-destroying pests like slugs.

“As I see it, neonicotinoids can provide good value in controlling critical pest species, particularly in vegetable and fruit production, and managing invasive species like the spotted lanternfly. However, I believe the time has come to rein in their use as seed coatings in field crops like corn and soybeans, where they are providing little benefit and where the scale of their use is causing the most critical environmental problems,” Tooker writes.

Jennifer Weeks is senior environment and energy editor with Reuters News Agency’s The Conversation. This story is a roundup of articles from The Conversation’s archive. It has been edited for length.