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4 essential reads on pesticides and the environment

<p>In 1962 environmental scientist Rachel Carson published “<a href="http://www.rachelcarson.org/SilentSpring.aspx" target="_blank" rel="noopener">Silent Spring</a>,” a bestselling book that asserted that overuse of pesticides was harming the environment and threatening human health. 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.</p> <p>“Silent Spring” is widely viewed as <a href="https://www.nytimes.com/2012/09/23/magazine/how-silent-spring-ignited-the-environmental-movement.html" target="_blank" rel="noopener">an inspiration for the modern environmental movement</a>. These articles from The Conversation’s archive spotlight ongoing questions about pesticides and their effects.</p> <h2>1. Against absolutes</h2> <p>Although the chemical industry attacked “Silent Spring” as <a href="https://www.penguinrandomhouse.com/books/170448/on-a-farther-shore-by-william-souder/" target="_blank" rel="noopener">anti-science and anti-progress</a>, Carson believed that chemicals had their place in agriculture. She “favored <a href="https://theconversation.com/would-rachel-carson-eat-organic-94967" target="_blank" rel="noopener">a restrained use of pesticides, but not a complete elimination</a>, and did not oppose judicious use of manufactured fertilizers,” writes Harvard University sustainability scholar <a href="https://wcfia.harvard.edu/people/robert-l-paarlberg" target="_blank" rel="noopener">Robert Paarlberg</a>.</p> <p>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.</p> <p>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.</p> <h2>2. Concerned cropdusters</h2> <p>Well before “Silent Spring” was published, a crop-dusting industry developed on the Great Plains in the years after World War II 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 href="https://theconversation.com/farmers-and-cropdusting-pilots-on-the-great-plains-worried-about-pesticide-risks-before-silent-spring-91976" target="_blank" rel="noopener">a much more cautious approach</a>,” recounts University of Nebraska-Kearney historian <a href="https://scholar.google.com/citations?user=37kbK3MAAAAJ&amp;hl=en" target="_blank" rel="noopener">David Vail</a>.</p> <p>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.</p> <p>Today aerial spraying is still practiced on the Great Plains, 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 <a href="https://www.usda.gov/oce/pest/integrated-pest-management" target="_blank" rel="noopener">has become mainstream today</a>.</p> <h2>3. The osprey’s crash and recovery</h2> <p>In “Silent Spring,” Carson described in detail how chlorinated hydrocarbon pesticides persisted in the environment long after they were sprayed, rising through the food chain and building up in the bodies of predators. Populations of fish-eating <a href="https://raptor.umn.edu/about-raptors/learn-about-raptors" target="_blank" rel="noopener">raptors</a>, such as bald eagles and ospreys, were ravaged by these chemicals, which thinned the shells of the birds’ eggs so that they broke in the nest before they could hatch.</p> <p>“Up to 1950, ospreys were one of the most widespread and abundant hawks in North America,” writes Cornell University research associate <a href="https://academy.allaboutbirds.org/person/alan-poole/" target="_blank" rel="noopener">Alan Poole</a>. “By the mid-1960s, the number of ospreys breeding along the Atlantic coast between New York City and Boston <a href="https://theconversation.com/ospreys-recovery-from-pollution-and-shooting-is-a-global-conservation-success-story-111907" target="_blank" rel="noopener">had fallen by 90%</a>.”</p> <p>Bans on DDT and other highly persistent pesticides opened the door to recovery. But by the 1970s, many former osprey nesting sites had been developed. To compensate, concerned naturalists built nesting poles along shorelines. Ospreys also learned to colonize light posts, cell towers and other human-made structures.</p> <p>Today, “Along the shores of the Chesapeake Bay, nearly 20,000 ospreys now arrive to nest each spring – the largest concentration of breeding pairs in the world. Two-thirds of them nest on buoys and channel markers maintained by the U.S. Coast Guard, who have become de facto osprey guardians,” writes Poole. “To have robust numbers of this species back again is a reward for all who value wild animals, and a reminder of how nature can rebound if we address the key threats.”</p> <h2>4. New concerns</h2> <p>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.</p> <p>But a growing body of research indicates that even though coated seeds are highly targeted, much of their pesticide load washes off into nearby streams and lakes. “Studies show that neonicotinoids are <a href="https://theconversation.com/farmers-are-overusing-insecticide-coated-seeds-with-mounting-harmful-effects-on-nature-176109" target="_blank" rel="noopener">poisoning and killing aquatic invertebrates</a> that are vital food sources for fish, birds and other wildlife,” writes Penn State entomologist <a href="https://scholar.google.com/citations?user=AAdZM1UAAAAJ&amp;hl=en" target="_blank" rel="noopener">John Tooker</a>.</p> <p>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.</p> <p>“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.</p> <p><strong>This article originally appeared on <a href="https://theconversation.com/silent-spring-60-years-on-4-essential-reads-on-pesticides-and-the-environment-192232" target="_blank" rel="noopener">The Conversation</a>. </strong></p> <p><em>Image: Shutterstock</em></p>

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Pesticide exposure makes it harder for bees to walk in a straight line

<p>Bees, long despised for stinging humans and pets, but loved by horticulturalists for their life giving goodness, are under attack like never before.</p> <p>In June research identified a dangerous variant of the deformed wing virus is <a href="https://www.sciencedaily.com/releases/2022/06/220601111805.htm#:~:text=Summary%3A,and%20the%20animals%20to%20die." target="_blank" rel="noopener">on the rise worldwide</a>. The virus infects honeybees, causing their wings to atrophy and the animals to die. </p> <p>Also that month the varroa mite, a major honeybee parasite, was discovered in biosecurity surveillance hives at the Port of Newcastle.</p> <p>Now new research has identified what happens to bees when they are subject to insecticides.</p> <p>Have you ever struggled to walk in a straight line after having one too many? Well, it seems that honeybees are having similar issues but after getting a dose of insecticides.</p> <p>“Here we show that commonly used insecticides like sulfoxaflor (kills aphids and lygus) and the neonicotinoid imidacloprid (pesticide that protects seeds of field crops) can profoundly impair the visually guided behaviour of honeybees,” <a href="https://www.scimex.org/newsfeed/bees-struggle-to-fly-in-a-straight-line-if-theyve-been-exposed-to-pesticides" target="_blank" rel="noopener">said lead author of a new study</a>, Dr Rachel H Parkinson from the University of Oxford.</p> <p>“Our results are reason for concern because the ability of bees to respond appropriately to visual information is crucial for their flight and navigation, and thus their survival.”</p> <div class="newsletter-box"> <div id="wpcf7-f6-p202420-o1" class="wpcf7" dir="ltr" lang="en-US" role="form"> <form class="wpcf7-form mailchimp-ext-0.5.62 spai-bg-prepared init" action="/earth/pesticide-exposure-bees-walk-straight-line/#wpcf7-f6-p202420-o1" method="post" novalidate="novalidate" data-status="init"> <p style="display: none !important;"><span class="wpcf7-form-control-wrap referer-page"><input class="wpcf7-form-control wpcf7-text referer-page" name="referer-page" type="hidden" value="https://cosmosmagazine.com/nature/" data-value="https://cosmosmagazine.com/nature/" aria-invalid="false" /></span></p> <p><!-- Chimpmail extension by Renzo Johnson --></form> </div> </div> <p>Insects have an innate ‘optomotor response’, which lets them orient themselves back onto a straight trajectory if they steer off-course while walking or flying.</p> <p>The research, published in <a href="https://www.frontiersin.org/articles/10.3389/finsc.2022.936826/full" target="_blank" rel="noopener"><em>Frontiers in Insect Science</em></a><em>,</em> challenged this optomotor response of walking honeybees by putting them in front of video screens of vertical lines which tricked them into thinking they’d moved off course.</p> <p>The vertical bars would move from left to right, or right to left which ‘tricks’ the bee into thinking it’s been blown off-course and needs to perform a corrective turn.</p> <p>The team of researchers looked at four groups of between 20-30 bees. The control had access to normal sugar water to drink, while the other three had different forms of insecticides added. One group had 50 parts per billion of imidacloprid, another had 50 parts per billion sulfoxaflor, and the last had 25 parts per billion of imidacloprid and 25 parts per billion of sulfoxaflor together.</p> <p>Unfortunately, the bees which had been exposed to the insecticide performed worse as they turned to get back on track. Bees exposed to pesticides seemed to have shallower turns and sometimes only turned one way. The asymmetry between left and right turns for example was 2.4 times greater for those bees exposed to pesticides.</p> <p>After this experiment, the researchers then had a look at the bee brains to look at the damage. Using molecular techniques, the team found that pesticide-exposed bees tended to have an elevated proportion of dead cells in parts of the brain’s optic lobes, which is important for processing visual input.</p> <p>Key genes for detoxification were also dysregulated after exposure. However these brain changes were relatively weak and highly variable across bees, and unlikely to be the sole explanation for the strong visual issues in the original experiment.</p> <p>“Neonicotinoid and sulfoximine insecticides activate neurons in the insect brain and are not always recycled fast enough to prevent toxicity,” said Parkinson.</p> <p>This research comes on the heels of a slew of other research in recent years suggesting that pesticides <a href="https://cosmosmagazine.com/nature/pesticides-impair-baby-bee-brain-development/">impair baby bee brain development,</a> or it can make <a href="https://cosmosmagazine.com/nature/neonicotinoids-make-bees-antisocial-and-lazy/">them antisocial and lazy</a>, and many scientists <a href="https://cosmosmagazine.com/earth/sustainability/scientists-call-for-urgent-action-on-bee-killing-insecticides/">are asking for them to be banned</a>.</p> <p><!-- Start of tracking content syndication. Please do not remove this section as it allows us to keep track of republished articles --></p> <p><img id="cosmos-post-tracker" style="opacity: 0; height: 1px!important; width: 1px!important; border: 0!important; position: absolute!important; z-index: -1!important;" src="https://syndication.cosmosmagazine.com/?id=202420&amp;title=Pesticide+exposure+makes+it+harder+for+bees+to+walk+in+a+straight+line" width="1" height="1" /></p> <p><!-- End of tracking content syndication --></p> <div id="contributors"> <p><em><a href="https://cosmosmagazine.com/earth/pesticide-exposure-bees-walk-straight-line/" target="_blank" rel="noopener">This article</a> was originally published on <a href="https://cosmosmagazine.com" target="_blank" rel="noopener">Cosmos Magazine</a> and was written by <a href="https://cosmosmagazine.com/contributor/jacinta-bowler" target="_blank" rel="noopener">Jacinta Bowler</a>. Jacinta Bowler is a science journalist at Cosmos. They have a undergraduate degree in genetics and journalism from the University of Queensland and have been published in the Best Australian Science Writing 2022.</em></p> <p><em>Image: Getty Images</em></p> </div>

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