Pesticides
Weeds and pests aren’t just ugly. They’re a threat. ~ American lawn-care provider TruGreen advertisement (2012)
In Nature, there are no pests. Humans label as pests any plants or animals that endanger our food supply, health, or comfort. To manage these pests we have pesticides. ~ American entomologist Keith Delaplane
Weeds are an index of what is wrong – and sometimes what is right – with the soil. Weeds shout out in understandable terms that something is wrong with the direction of decay of organic matter. ~ American agriculturist Charles Walters Jr.
Pesticides are chemicals intended as a biocide: a killer of life. Herbicides are the most widely used pesticide, followed by insecticides and fungicides. Pesticides are most commonly used to protect crops at the expense of all else in the environment.
Chemists concoct pesticides for efficacy on the intended pest. The externalities of pesticides, which are extensive, are an after-thought, if given any thought at all.
Ideally a pesticide must be lethal to the targeted pests, but not to non-target species, including man. Unfortunately, this is not the case. The rampant use of these chemicals, under the adage, “if little is good, a lot more will be better” has played havoc with human and other life forms. ~ Indian pesticide researcher Wasim Aktar et al
The most common pesticides are toxic and carcinogenic to humans. Developed in the 1950s and 1960s, and used extensively since, they ravage all animals’ nervous systems, and are also detrimental to plants.
Malathion is the most common insecticide: frequently used to treat fruit, vegetables, and plants for pests, as well as put on pets to remove ticks. Chlorpyrifos is employed to exterminate termites, mosquitoes, and roundworms. Diazinon is often used on cockroaches, ants, and fleas. All 3 are poisonous nerve agents, injurious to all animals in the same way they kill insects and other little critters, which suffer greater toxicity only owing to their tiny size.
The EPA has allowed chemical companies to register more than 16,000 pesticides without properly considering their impacts. These dangerous pesticides have been used without proper analysis for decades. ~ American environmental scientist Lori Ann Burd
Pesticides sprayed on fruits and vegetables accumulate on the outer skin; but the skin is not an impermeable barrier, and some pesticides are actually designed to be absorbed into the tissue of the fruit or vegetable. The produce most contaminated in the US are strawberries, spinach, nectarines, apples, peaches, celery, grapes, pears, cherries, tomatoes, sweet bell peppers, and potatoes.
History
Famers have always lived at the mercy of the Nature they hope to exploit, determined to rule the land, yet subject to the vagaries of soil and sun, wind, and rain, to sudden outbreaks of crop diseases, to unpredictable invasions of insects and other pests. ~ American chemist James Whorton
The plying of pesticides extends into antiquity. Farmers in ancient Sumer dusted sulfur on their Mesopotamian crops 4,500 years ago. Contemporaneous Indian texts mention using poisonous plants for pest control.
Ancient Romans slayed insects by burning sulfur. Weeds were treated with salt.
By the 15th century, toxins such as arsenic, mercury, and lead were applied to crops to kill pests. In the 1600s, ants were fed a mixture of honey and arsenic.
Organic pesticides were also employed. Beyond their ample use as produce, plants have long been treasured as both medicines and toxins.
Pyrethrum, derived from chrysanthemum flowers, is an insecticide known since 400 bce. In the Middle East, pyrethrum Persian powder long served as a lice remedy.
Rotenone is got from the seeds and roots of tropical plants. It is a broad-spectrum killer that stymies electron transport in the mitochondria of cells. Rotenone had been used to poison fish for centuries before it became popular as an insecticide in the mid-19th century, particularly for caterpillars.
Chemists in the 17th century extracted nicotine sulfate from tobacco leaves as an insecticide. By the late 19th century, US farmers were applying a variety of chemicals to field crops to kill insects. The results were often unsatisfactory, owing to the primitive chemistry and inapt application.
The rise of modern pesticides began after World War 2, when a variety of potent formulas found favor. Among them were DDT and 2,4–D. These were products of government-sponsored research during the war: potent pesticides that were quickly adapted to civilian use when the guns stopped. The triumphalist rhetoric used to describe the war effort was readily translated into the need to fight and win the war on pests.
Get rid of weeds – now that chemistry had developed an easy, economic method for their destruction. ~ 1946 herbicide advertisement
These new chemicals were inexpensive and enormously popular. Americans were especially enthusiastic and naïve in their embrace of modern technologies and view of economic growth as progress. Another aspect was the mistaken assumption that increasing agricultural output was by definition good, and that this bounty was inextricably tied to modern techniques, particularly pesticides.
Airplanes swoop over a field leaving a trail of vapor, engaged in chemical warfare against crop-destroying pests. You’ll also see spray machines squirting selective chemicals which kill weeds but don’t harm the crops. ~ Saturday Evening Post (23 October 1954)
Lulled into a false sense of security about “better living through chemistry,” people liberally applied pesticides in pursuit of habitats “sterilized” of pests. In the 3 decades following World War 2, pesticide use in the US leapt tenfold.
By the end of the 20th century, the post-war chemical revolution was an entrenched institution. Synthetics of all sorts pervaded modern life. Pesticides were merely exemplary.
Since the mid-1940s, over 200 basic chemicals have been created for use in killing insects, weeds, rodents, and other organisms descried in the modern vernacular as “pests.” These sprays, dusts, and aerosols are now applied almost universally to farms, gardens, forests, and homes – nonselective chemicals that have the power to kill every insect, the “good” and the “bad,” to still the song of birds and the leaping of fish in the streams, to coat the leaves with a deadly film, and to linger on in soil – all this though the intended target may be only a few weeds or insects. Can anyone believe it is possible to lay down such a barrage of poisons on the surface of the Earth without making it unfit for all life? They should not be called “insecticides,” but “biocides.” ~ American marine biologist Rachel Carson in Silent Spring (1962)
Under constant chemical attack, some victims developed genetic resistance. Meanwhile, the swath of environmental damage was far more than reckoned.
DDT
DDT is now so universally used that in most minds the product takes on the harmless aspect of the familiar. ~ Rachel Carson in 1962
DDT is a crystalline organochloride that is colorless, tasteless, and almost odorless. An organochloride is a class of compounds that are chlorinated hydrocarbons. Chlorination modifies a hydrocarbon’s properties, typically in ways sinister to life. In the case of DDT, a prevalent action is disrupting sodium activity in an animal’s nerve cells.
DDT was first synthesized in 1874. Swiss chemist Paul Müller discovered DDT’s apocalyptic insecticidal activity in 1939. Hailed as the means for winning the war against 6-legged destroyers of crops, Müller won the Nobel Prize in 1948.
DDT is harmless to man, so far as the evidence goes. ~ The New York Times in 1944
The American military sprayed DDT in Europe and the Far East during World War 2 and marveled at its lethal potency. When the war ended, DDT garnered vast application, celebrated as “the atomic bomb of the insect world.”
The praise was on-point. DDT and other synthetic pesticides wreak their havoc through death-dealing ionization.
The damage caused by the ionization of atomic fallout and by chemical agents are the same. ~ Italian chemist Americo Mosca
The appreciation of DDT’s vigor turned to alarm with the seminal 1962 book Silent Spring, in which Rachel Carson detailed the persistent threat that DDT and other synthetic “elixirs of death” had on all animal life. Though the USDA fought it, the book led to the 1972 ban on DDT for agricultural use; a ban that became worldwide only in the early 21st century. (USDA = United States Department of Agriculture)
DDT is still used in Africa and South America to control insect-borne diseases, such as malaria. Some countries, including India and North Korea, continue to apply DDT to crops.
DDT is readily adsorbed into soils and sediments, where it exposes itself to organisms for decades. DDT works its way up the food chain, thus incrementally improving its toxicity on larger predatory animals. DDT is carcinogenic.
Neonicotinoids
Insect pollination is a vital ecosystem service that maintains biodiversity and sustains agricultural crop yields. ~ English animal ecologists Richard Gill & Nigel Raine
While DDT is ostensibly banned, it is only one of many in the 1st generation of synthetic pesticides, several of which remain in use. In succeeding generations of pesticides, chemists thought themselves clever by synthesizing variants of molecules that plants themselves produce to ward off their pests. An obvious candidate was nicotine. Neonicotinoids were developed in the late 1980s.
Neonicotinoids mimic the action of neurotransmitters. In doing so, they continuously stimulate neurons, leading ultimately to death of target invertebrates. Like virtually all insecticides, they can also have lethal and sublethal impacts on non-target organisms, including insect predators and vertebrates. ~ Dutch entomologist and ecologist Noa Simon-Delso et al
Neonicotinoids are quite good at killing insects. In most instances it takes a few mere molecules per billion, equivalent to a few drops in a swimming pool of water.
Neonicotinoids found favor for their supposed specificity: they were not as lethal to larger animals as insects. Neonicotinoids became wildly popular.
Being water soluble, neonicotinoids leach into ponds, ditches, and streams and contaminate groundwater. Waterways with neonicotinoids have depleted insect abundance and diversity. ~ Dutch biologist Maarten van Lexmond et al
There is strong evidence that soils, waterways, and plants in agricultural environments and neighboring areas are contaminated with neonicotinoids and their metabolites. ~ French ecologist and chemist Jean-Marc Bonmatin et al
Neonicotinoids can persist for years in soils, and so cause environmental concentrations to build up. ~ Maarten van Lexmond et al
Besides spraying, neonicotinoids are slathered on seeds to prevent their being eaten by bugs. Beyond killing pollinating insects, severely polluting seed-eating birds, and other environmental degradation, that tactic is useless.
Neonicotinoids otherwise have had quite an impact. They pummel the primary pollinators upon which all crops rely: bees. Honeybee colonies suffered terribly after the introduction of neonicotinoids, yet it took scientists decades to ascertain the obvious: insecticides hurt insects.
Neonicotinoids are highly likely to be responsible for triggering ‘colony collapse disorder’ in honeybee hives that were healthy. ~ Chinese American ecologist Chensheng Lu
Repeated exposure to even low doses of neonicotinoids befuddles bees, enfeebling their foraging. This impairs their pollination services, which are crucial to healthy ecosystem functioning.
Insecticides have a significant negative impact on bee learning and memory. This occurs even at the low levels of pesticides that bees would routinely encounter in the field. ~ English biologist Harry Siviter
Still the lesson has yet to sink in. Neonicotinoids continue to be massively employed – business as usual until a silent spring, as Rachel Carson feared.
It is not clear, based on current research, whether pesticide exposure is a major factor associated with US honeybee health declines. ~ US Department of Agriculture in 2012
As aforementioned, neonicotinoids are merely more toxic to insects than mammals. Unsurprisingly, these pesticides damage fish, avian, and mammalian nervous systems too.
Although vertebrates are less susceptible than arthropods, consumption of small numbers of dressed seeds offers a potential route for direct mortality in granivorous birds and mammals, for such birds need to eat only a few spilt seeds to receive a lethal dose. Lower doses lead to a range of symptoms including lethargy, reduced fecundity, and impaired immune function. ~ Maarten van Lexmond et al
Early exposure to pesticides is especially destructive, causing developmental detriments, including autism in children. Autism has surged in the US in the 21st century owing to pollution. The state with largest leap is New Jersey, which is heavily polluted, due partly to hosting many toxic chemical plants.
Far from protecting food production, the use of neonicotinoid insecticides is threatening the very infrastructure which enables it. ~ Jean-Marc Bonmatin
Pesticides simply are not ecologically sensible. Their effects are more damaging, and widespread, than has been assumed. Honeybees and other pollinators are poisoned by pesticides on plants that were never sprayed.
In the past, we underestimated the risks of widely used pesticides. ~ Chinese ecologist Guangming Zeng et al
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The first duty of the agriculturalist must always be to understand that he is a part of Nature and cannot escape from his environment. He must therefore obey Nature’s rules. ~ Albert Howard
A significant fraction of the temporary productivity gains in agriculture during the Green Revolution are attributed to the pesticide use.
It is astonishing we have learned so little. After Silent Spring revealed the unfortunate side-effects of those chemicals, there was a big backlash. But we seem to have gone back to exactly what we were doing in the 1950s. It is just history repeating itself. The pervasive nature of these chemicals mean they are found everywhere now. ~ English ecologist Dave Goulson
2.7 million tonnes of pesticides are applied worldwide every year. The US sprays 22% of the pesticides: 600 tonnes, an average of 1 kg per hectare of arable land.
Despite heavy dosing, the US does not use pesticides as intensely as some other countries. Japan smears 5.9 kg of pesticides per hectare on its crops; China 4.7 kg; Italy 2.5 kg; and 1.3 kg per hectare in the British Isles.
Besides grotesque overapplication, pesticides are not very effective. At best, only 1% reach their intended target.
Not using pesticides reduces crop yields by only ~10%; even less if crops are planted with vegetative buffers (polyculture) to give ravenous insects something else to eat and help disguise the food hoard so as not to blatantly advertise and attract the little buggers in the first place. But that sort of smart farming is practiced practically nowhere. Instead, monocropping is ubiquitous.
Further, the meager positive power of pesticides has waned. From 1950 to 2000, despite increasing pesticide use by 800%, US crop losses from insects nearly doubled: from 7% to 13% of the total harvest.
There is a chance for an immunity to manifest itself in increasing degree as the insects become acclimatized. ~ American entomologist A.L. Melander in 1914
Evolved resistance to insecticides and herbicides has been known for well over a century. The chemists who concoct killer compounds only care that their creations destroy the intended targets without being lethal to humans in the applied doses. All else is incidental.
Insect and weed evolution may outstrip our ability to replace outmoded chemicals. ~ American entomologist Fred Gould
It is not a matter of if but when we are going to lose chemical control of weeds. ~ American botanist Adam Davis
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Industrial agriculture has become a war against ecosystems. The chemicals on which industrial agriculture is based were originally designed for chemical warfare. ~ Vandana Shiva
Ultimately, pesticides affect all members of an ecosystem, from the tiniest invertebrates to humans and other large animals living at the top of their food chains. ~ American pesticide maven Monica Moore
Deadly Adjuvants
Billions of pounds of formulation and tank adjuvants, including organosilicone adjuvants, are released into US environments each year, making them an important component of the chemical landscape to which bees are exposed. ~ American entomologist Julia Fine
Adjuvants are substances added to pesticides and herbicides to improve their performance. Owing to potency, one of the most widely used is organosilicone, which is applied to wine grapes and tree fruits, including almond trees. These chemicals are commonly used during crop blooming periods, when pollinators are most present.
There are no regulations on use of adjuvants, as the US EPA classifies them as biologically inert. But that is not true. Honeybees exposed to organosilicone adjuvants are much more susceptible to viral infection, and more likely to quickly succumb.
The adjuvant is enhancing the damaging effects of the virus. It causes synergistic mortality. ~ Julia Fine
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When earth is rich it bids defiance to droughts, yields in abundance, and of the best quality. ~ American farmer and US President Thomas Jefferson
The effects of pesticides run deep. Herbicides reduce earthworm casting, which promotes soil health. The toxins damage earthworm fertility, and so hurt soil quality.
In a natural environment, topsoil builds via decaying plant matter and weathering rock. The soil is protected by erosion by growing plants.
In soil made vulnerable by agriculture, erosion reduces productivity by up to 65% per year.
The former prairie lands that constitute the US breadbasket have lost half of their topsoil after being farmed for a century. Soil is eroding 30 times faster than the natural formation rate.
It takes 500 years for Nature to replace an inch of topsoil. Reforming damaged topsoil to a depth for agriculture takes 3,000 years.
Food crops are much hungrier than the parsimonious grasses that once covered the Great Plains. Much of the soil there is now little more than a sponge into which synthetic fertilizers are poured to produce crops.
Erosion rates are rising throughout the world.
China is losing 36 tonnes of topsoil per hectare each year. During the spring planting season, Chinese soil can be found in the air as far away as Hawaii.
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China exceeded its capacity to feed itself by the late 1980s. The Chinese import prodigious quantities of grain while pushing their croplands to the limit with artificial fertilizers and pesticides to eke out what they can.
Agricultural productivity has declined in parts of Africa by 50% due to soil erosion and desertification. (8,000 years ago, agriculture and the introduction of livestock in North Africa culminated in the creation of the Sahara Desert, which had before been verdant land.) Production losses in the range of 20% have been reported in India, Pakistan, and several Middle Eastern countries, thanks to the farming practices advocated by Green Revolutionaries.
Contrary to the myth that industrialized agriculture is superior, studies have shown that indigenous natural systems are more efficient in terms of yields, labor, and energy.
Both from the point of view of food productivity and of food entitlements, industrial agriculture is deficient as compared to sustainable farming systems based on diversity and internal inputs. ~ Vandana Shiva
Further, agriculture reliant upon chemical fertilizers and pesticides is environmentally unsustainable: the toll on the soil and pollinators is too much for plants to bear.
All the great agricultural systems which have survived have made it their business never to deplete the earth of its fertility without at the same time beginning the process of restoration. ~ Albert Howard
Pollinator Downfall
The whole fabric of our planet is built on plants and insects, and the relationship between the two. ~ American ecologist Scott Black
Birds, bees, butterflies, beetles, bats, and wasps all have 2 things in common: they pollinate plants, and their numbers are dwindling fast.
Pollinators play a key role in the agricultural system, which also employs millions of humans to feed their world. 35% of the crops grown worldwide, with an annual value of $577 billion, depend upon pollination.
Flying insects have really important ecological functions, for which their numbers matter a lot. Flies, moths, and butterflies are as important as bees for many flowering plants. Flying insects provide food for many animals. Flies, beetles, and wasps are also predators and decomposers, controlling pests and generally cleaning up the place. ~ English zoologist Lynn Dicks
The abundance of flying insects in German Nature preserves plunged by 76% in the quarter century 1989–2016. That finding is likely to be typical of the worldwide trend.
This decline happened in Nature reserves, which are meant to preserve biodiversity and ecosystem functioning. ~ Dutch ecologist Caspar Hallmann
Insects make up about 2/3rds of all life on Earth, but there has been some kind of horrific decline. We appear to be making vast tracts of land inhospitable to most forms of life and are currently on course for ecological Armageddon. If we lose the insects, then everything is going to collapse. ~ Dave Goulson
Many pollinators face impending extinction, including at least 9% of bees and butterflies, and 16% of nectar-loving vertebrates like birds and bats.
In the US, beekeepers lost 41% of their honeybee colonies in 2018. This continued a 21st-century trend of accelerating debility in commercial colonies.
The causes of the decline are entirely man-made. Farming, roads, and buildings eliminate wildflowers and other plants pollinators depend upon. Decades of pesticides have decimated insect populations, and weakened those left alive, leaving them easy prey to parasites and pathogens. Honey all around the world is contaminated with pesticides known to harm honeybees.
Even managing pollinators takes a toll. Trucking honeybee hives around, as done extensively in the US, is disorienting to the captives. Their health suffers, and so contributes to pollinator decline.
If you look at what’s driving honeybee declines, industrial agriculture certainly plays a major role. ~ American geoscientist Kelly Watson
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Theoretical computer modeling suggests that plants can tolerate losing most pollinator species as long as other pollinators take up the slack. Instead, the plant-pollinator relationship is not so casual. Sustaining relations during a flowering season are important to plant fecundity. In a study of Rocky Mountain larkspur wildflowers, removing a single bumblebee population from pollinating services had profound consequences.
These wildflowers produce 1/3rd fewer seeds in the absence of just 1 bumblebee species. ~ American ecologist Berry Brosi
While particular flower populations are in bloom, certain insect pollinators favor them with fidelity, thus maximizing cross-pollination among the plants.
Most pollinators visit several plant species over their lifetime, but often they display floral fidelity over shorter time periods. They’ll tend to focus on one plant while it’s in bloom, then a few weeks later move on to the next species in bloom. You might think of them as serial monogamists. ~ Berry Brosi
When bees are promiscuous, visiting plants of more than one species during a single foraging session, they are much less effective as pollinators. ~ American biologist Heather Briggs
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A 2016 survey revealed that US crop production is in dire threat from pollinator downfall. The foolishness of assuming it was safe to spray pesticides at industrial scales across entire landscapes is a harbinger of doom.
