Bugged Page 12
“Roach Chow,” one of the bigger precursors to modern household pest control, actually had low toxicity. Invented by P. F. Harris in 1922, these boric acid tablets staved off cockroaches, ants, silverfish, and termites by damaging their exoskeletons and attacking the cellular lining of their guts, ruining their metabolism. In 1924, to prove its effectiveness, Harris aided the White House in killing off hordes of insects. “Once they get my stuff inside them,” he told a Washington Times reporter of his natural mineral, “they are done for.” (A similar guarantee for certain motels: “Roaches check in, but they don’t check out!”) Harris’s campaign yielded five pounds of dead insects. As of 1979, a family home in Schenectady, New York,11 has the honor of having had world’s largest cockroach infestation with over 1 million bugs. Exterminators for this operation filled pucks with a bait called Maxforce (you know it today as Combat), which first poisons a portion of the horde and more ex post facto via roaches feeding on toxic poop.
But what of long-term success? Contrary to what the ant-like Borgs of Star Trek say, resistance is inevitable. German cockroaches, North Carolina State University scientists discovered in 2013, are no longer “checking in” to Roach Motels. They’ve adapted. The once-tasty glucose used in Black Flag products, thanks to a rapidly evolved genetic mutation, now tastes bitter to cockroaches. Our search for a “magic bullet”—or bullets—has led to today’s endless rotation of bait inventions and insecticide sprays. Today the monetary toll of now-resistant pests is about $60 billion per year.
Insects were able to defeat what the comic book geek in me calls the Four Horsemen of the Bugocalypse. Chemical admixtures developed initially as an agricultural means of control whose use transitioned into one of annihilation. The result was increased resistance, ecological disruption, and loss of human life. The First Horseman that marks this epoch was known as Paris green. “The rise of Paris green left a historical legacy of ambivalence to toxic insecticides,” writes Bugs and the Victorians author J. F. M. Clark. And it began with the eastward march of the voracious Colorado potato beetle.
In the mid-1800s, fields across the United States became giant salad bars for the black and yellow beetle, which is capable of laying up to 800 eggs. In their larval form, they can consume up to 40 square centimeters of foliage a day. By the 1870s, illustrated WANTED posters for the now-transatlantic beetle were created by UK customs, informing inspectors and workers that “the Insect if seen, to be crushed at once.” This angered entomologists trying to get samples for proper ID-ing. In the United States, people began applying to crops an emerald paint pigment containing arsenic known as Paris green. A Michigan man reportedly first used Paris green—intended to kill rats in its eponymous city—against beetles in 1867. It was confirmed as an effective insecticide in 1871 by USDA entomologist C. V. Riley—an important figure in this war. Bureau of Entomology chief L. O. Howard also helped guide the rising trend of arsenic- and lead-based chemical control. The attraction was clear to nineteenth-century agriculture writer Frank Sempers. Tell a cabbage farmer that one ounce of powder will kill leaf-eating worms in a day or two, he says, and society’s reluctance to using poison on crops diminishes. (Lead arsenate wasn’t banned until 1988.) Although it initially worked on the beetles, its downsides soon came to light. The highly neurotoxic copper acetoarsenite caused a chronic “pins and needles” feeling in some of the people who applied it.12
Its use continued. A South Carolina plant disease treatment book from 1909 gives tips and recipes on different Paris green admixtures. It mentions that “burning foliage” is to be expected: “Some of these apparatuses are provided with gauges which will enable one with good judgement to apply the powder very rapidly in concentrated form.” How the words “good judgement” made the cut beats me. The guidebook also mentions what might be considered our Second Horseman: hydrocyanic acid gas (HCN).
HCN, an inorganic insecticide smelling of bitter almonds, first came into use in 1886 to fight wood-plant grubbing scale insects. One of the most toxic fumigants used up to that time period, it also became a means of delousing. Later HCN was released by brands like DuPont under various names, and is still used occasionally today. (Agriculture comprises about 90 percent of the $13 billion insecticide market, which includes companies like Bayer and Dow.) It had the miraculous effect of paralyzing pests. A 1933 Cyanogas ad with a man wielding a cyanide gas backpack beckons, “Fight the hoppers! Enlist with me against the grape leaf hopper.” Similar industry advertising and government-led campaigns reinforced insect hostility. It seems as though we are ages from what entomologist Julian West called the “Period of Friendly Tolerance” of houseflies before the twentieth century. HCN’s standard use involved enclosing groves with a tarp and then releasing the cyanide gas. Similar enclosed use was administered for indoor bedbug fumigations—with obvious fatal results. People—professionals and residents—were at risk of first becoming unconscious and then dying of asphyxiation. In perhaps the lowest point of human history, HCN was also found in Zyklon B, the cyanide gas used during the Holocaust.
Like other inorganics, HCN use began to dwindle. “By the early 1940s,” writes historian John Ceccatti, “field researchers had identified about ten agricultural pests and laboratory strains that were capable of withstanding exposures to insecticides that had previously been highly effective in killing these same species.” Arsenic and cyanide became pointless chemical baths. But World War II helped introduce a juggernaut that brought attention to resistance. It was known as DDT, or the Third and most powerful Horseman of the Bugocalypse.
“The story of DDT,” writes Dawn Day Biehler, “dovetails with that of postwar suburbanization, consumerism, and notions of modern homes.” Housewives became generals in the War on Bugs. The compound, dichloro-diphenyl-trichloroethane, became famous for its comparatively lower toxic effects on mammals. The other side of that coin, as pointed out by Fumio Matsumura (“grand master of insect toxicology”), caused “environmental endocrine disruptions.” Like the aforementioned pyrethroids, DDT thwarts an insect’s sodium channels. And as with pyrethroids, insects evolved quickly to fight it. Unlike other insecticides, however, DDT brought international attention to resistance after it had lowered the volume of Earth’s buzzy fiends for a short amount of time.
Disease-related fatalities dropped significantly after World War II because of DDT. Italy didn’t experience one malaria-related death between 1949 and 1950. Any insect that came into contact with DDT was obliterated. By the mid-1950s, 100 million pounds had been produced, diluted into household products, powders, sprays, and infused wallpaper. Advertisements billed it as a “miracle powder.” Section 8 homes were regularly treated with DDT. Over a 30-year period, the United States used over 675,000 tons domestically. The president of the American Association of Economic Entomologists estimated that 5 million lives were saved.
Then in 1962 an atomic awareness bomb dropped in the form of Rachel Carson’s Silent Spring. “The insect enemy has been made stronger by our efforts,” Carson said. “Even worse, we may have destroyed our very means of fighting.” By 1948 scientists had already heard confirmations of a burgeoning worldwide resistance. But now DDT became the “cause célèbre that ignited the environmental movement,” writes Will Allen. The ecological chain reaction caused reproductive issues for birds (such as thinner eggshells) and aquatic species. Until then, biological control of insects, first introduced by C. V. Riley, had gone by the wayside. But even after DDT’s ban in 1972, undeveloped nations relied on the immediate action of pesticides as more elegant methods were not readily available. Again, the aftermath was dire. According to a World Health Organization report from 1989, pesticides were poisoning 1 million people a year worldwide—approximately 20,000 died. After the 2004 Stockholm Convention on Persistent Organic Pollutants, DDT was limited to vector control only.
The EPA finally regulated a good portion of such toxins with the Food Quality Protection Act of 1996. I leave the seat of the Fourth Horseman … unoccupied. Resist
ance, just like viruses, constantly evolves in our attempts to treat it. A certifiable weapon against insects will not come into existence in our lifetimes. However, what can lead the way, at least for portions of time, is a mash-up of biological control.
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Many scientists believe that nature can combat nature and that synthetic chemicals only complicate matters. Even C. V. Riley, the “father of biological control,” expressed doubts about Paris green. He and two other scientists drove out scale bugs from California citrus groves by introducing Australia’s vedalia beetles in 1888. In the wake of this success, entomologists traveled the globe searching for beneficial insects. The enemy of my enemy is my friend and all that jazz. “Every insect has its predator which follows and destroys it,” Carl Linnaeus remarked in 1752. “Such predatory insects should be caught and used for disinfecting crop-plants.” He was right. Eighty-five such biological control agents were put on trial and implemented from 1920 to 1940. Up to the present day, there have been 1,200 such projects. At times, the “benefit-to-cost” ratio of biological control as opposed to pesticide treatment, according to two researchers, can be 200 to 1.
A similar citrus issue sprang up in Israel around 1938 with mealybugs, so the Palestine Farmers Federation shipped several parasitoid species from Japan, including encyrtid wasps. Within three years after cultivation and release they’d snuffed out mealybugs. Other such integrated pest management (IPM) techniques might include pheromone traps, crop rotation, or shorter production seasons (which saved Texas from pink bollworm in the 1930s). Russian entomologist Elie Metchnikoff introduced the use of fungal pathogen Metarhizium anisopliae to control grain beetles in 1878. Sprinkled over fields and active for 11 months, it ended up being more effective against the sugar-beet weevils than any other means. Metchnikoff later moved to Paris’s Pasteur Institute to continue researching entomopathogens to control pests, such as green cabbageworms. Another disease, called Wipfelkrankheit,13 used to control insects, killed swaths of nun moths.
Despite IPM’s slow but valuable controls, synthetic organic insecticides boasted more immediate results. From 1964 to 1982, such chemical usage increased 170 percent in weight, according to a paper in The Economic Journal. A survey from the late 1980s found that 40 percent of farmers were dissuaded from using IPM simply because they were uncertain of its effectiveness. According to University of Arizona professor Bruce Tabashnik, incidences of insect resistance to pesticides went up by 61 percent from 2000 to 2010. (That’s from 6,617 records of resistance to 10,661.) “There’s a reason [insects] have in essence conquered the world,” says Tabashnik. “In terms of their numbers, their diversity and their widespread geographic distribution … This is a never-ending race. This is a never-ending conflict.”
The increasing attraction to IPM has turned farmers on to transgenic crops engineered with genes from natural bacteria. In 1911, Bacillus thuringiensis (Bt) was found to kill flour moth larvae. And in the past two decades, since Bt became commercially available, farmers have gravitated to crops engineered with it. Such GMOs comprise over 79 percent of corn and 84 percent of cotton crops in the United States. But if mishandled, moth larvae can become resistant. This is where Bruce Tabashnik comes in. To annihilate seed-eating pink bollworms in Arizona—a century-long “scourge”14—Tabashnik helped devise a plan incorporating strategic placement of Bt crops. Here’s the twist. Rather than leave it to Bt alone, the plan pushed the use of sterile insect technique (SIT)—a process developed in the 1950s—to wallop male moths with radiation.
“A combination of techniques can be much more powerful than just their sum,” he says, talking like a military colonel. “They work together synergistically.” Once ingested, the Bt bacteria “punch[es] holes” into the gut lining of caterpillars. In the rare case that a resistant moth finds another resistant adult, “then they’re off to the races.” But by combining Bt crops with SIT, the chance of that outcome is reduced significantly. Starting in 2006, collaborating with the USDA, cotton growers, and the University of Arizona, the team began releasing sterile bugs. (Problems arise if SIT is used alone. In one instance involving codling moths, reduction tapered off around the fifth year of releases.) To detect if the technique was working, traps were set up, similar to Oxitec’s GM mosquito project. “Don’t rely on one thing,” Tabashnik says about our future pest management. “That’s a bedrock principle.” What it takes, he says, “is a combination of tactics.”
Pink bollworm in Arizona will be declared officially eradicated once the USDA gives the word. Yet Bt is a limited promise. Tabashnik believes his group’s success should last decades. But human fallibility and insect evolution are, again, inevitable. Each type of Bt is a narrow-spectrum bioinsecticide. Some types of the bacterium kill only caterpillars, or only beetle larvae or mosquito larvae. Other dubious foes include aphids, mealy bugs, stink bugs, and other sucking insects.
Pam Marrone, an ex-employee of Monsanto in a pesticide industry full of heavy-duty chemicals, is at the forefront of organic insecticides. Marrone grew up in southern Connecticut on a mini-farm in the late 1960s, a child of the Silent Spring era. And one of her vivid memories is of the local gypsy moth caterpillars. “I would be standing in the woods,” she says during a phone chat, “and literally insect poop would be raining down on my head. There were so many caterpillars munching.” She recalls the midsummer forest looking as depleted as though winter had arrived early.
What happened next changed her life. Her dad bought a highly toxic insecticide called carbaryl. After applying it, the caterpillars came down. This was then followed by a downpour of ladybugs, lace wings, honeybees … “My mother had a fit,” she remembers. Her father then returned home with Bt, and from then on Marrone pursued microbial insecticides “single-mindedly.” Natural remedies were a part of her upbringing. Her grandparents used folkish methods imported from Italy and Poland. Her mother taught her at-home organic treatments like grinding hot peppers into a spray admixture. “Now it was becoming a science.”
Organic insecticides are clearly a growing trend. Companies like Terminix seek alternatives to crude chemicals. EcoSMART introduced plant-based oil insecticide. DOW partnered with a pharmaceutical company to discover insect-killing microbes. Scientists now dedicate their lives to finding IPM solutions. At Monsanto, in 1983, Marrone was a “kid in a candy shop,” exploring the potential of 100,000 different microbes and ancient pest control methods. Later, after screening 77,000 microbes, she’d start Marrone Bio Innovations. Though her company is small, they’ve sold 1.69 million gallons of microbial-based biopesticides as of 2015, treating 2.4 million acres and targeting the other pests that Bt can’t hit. This is small potatoes compared to the $55 billion in chemical pesticides sold globally today. (Biopesticides account for $3 billion.) But it is a healthier broad-spectrum solution rooted, Marrone’s research has shown, in old techniques.
Attempts at putting pests in a fatal chokehold have been around for millennia. A Scientific American article from 1848 talks about burning peat as a means of fumigating bedbugs: “Peat in burning gives out a singular odor, which is very disagreeable to some, but which banishes that pest to mankind from houses, the bedbug.”
The fumigation practice of burning sulfur is first documented by Sumerians in 2500 BCE, and is again referenced in The Odyssey: “Bring sulfur, old nurse, that cleanses all pollution, and bring me fire, that I may purify the house with sulfur.” Another fascinating example: Greeks and Romans using a boiling mixture of bitumen, sulfur, and amurca—sediment from unfiltered olive oil—to keep caterpillars from decimating their vineyards. Our agricultural elders, they used natural resources to prevent infestations.
I ask if Pam Marrone has ever heard of the Geoponika—a 20-book series that compiles Mediterranean agricultural practices possibly as far back as 1300 BCE. Not only has she heard of it, but her scientists experimented with some remedies 18 years ago. After some thought, I decided to give it a shot too.
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The Geopon
ika describes the practice of tying captured bats to “tall trees,” write researchers Allan Smith and Diane Secoy. Their screeches would deflect locusts from farms. Scattering powdered stag antlers on seeds was believed to repel worms. And an application of bear’s blood, goat fat, or frog’s blood to pruning knives supposedly deterred insects and larvae. Coating cabbages with amurca and ox urine was said to have promising results. Amurca also acted as a pseudo-mothball that protected clothes and helped prevent ants from invading when smeared on floors. Staking a horse’s skull in a garden like a medieval scarecrow fazed caterpillars. That goes double for nude, menstruating women dancing barefoot through the garden with “unbound hair.” An owl’s heart hung over crops repelled snails and beetles. So did the tilapia fish dangling from trees. Some Greeks recommended burnt seashells for mosquito repellent, while certain African tribes daubed cattle urine on themselves with the same hopes. And in Japan one remedy for keeping away nighttime crawlies was to place soft seaweed around children’s beds.
Magic and folklore are the origins of pest control. Truly, they are as comparatively absurd as practices used in the past 150 years. And as many farmers do today, prayer offerings15 were made regularly. Still, the question at hand is: does any of it actually work?
Bitter apple spray was used by Greeks to fight off fleas. Goldmoss stonecrop flower was used circa 300 BCE to infuse seeds as a preventive measure. Arsenic was used in China as early as 200 BCE. A combo of milk-softened hellebore and arsenic worked against flies. Oil was sprayed on granaries to upend beetles. During the Renaissance, “tobacco infusions” were recommended as a means of controlling pear infestations. Tobacco of course contains nicotine, which is still used in insecticides dubbed neonics.