Our industrial agricultural system relies heavily on pesticides, which control weeds, kill insects and stave off fungi. More than 1.1 billion pounds of pesticides are applied annually to crops in the US, and many weed-killers are used in combination with seeds that are genetically engineered to withstand them. The escalating use of pesticides in recent decades has become a public health hazard, an environmental disaster and has even caused the evolution of “superweeds,” which require increasingly toxic pesticide formulas to overcome them. Consumers can help reduce the demand for products grown with pesticides by purchasing organic or low-spray produce and by joining organizations building power against the powerful multi-billion-dollar pesticide industry.
Industrial agriculture relies on two types of chemicals: fertilizers and pesticides. The former boosts soil fertility, making crops more productive, while the latter protects crops by controlling weeds (herbicides), insect and animal infestation (insecticides and rodenticides) and fungal/mold diseases (fungicides).1
Pesticides come in a variety of applications that treat everything in their path, making specific targeting of a particular pest or disease impossible. For example, fumigants are applied as gases to the soil, and “systemic” pesticides function by migrating through a plant’s cells to get absorbed by the roots later. The problem with these methods is that they cause harm to the entire system, instead of just their intended targets. This means that soil, usually alive with many different organisms, many of which are beneficial to plant life and healthy ecosystems, is effectively “killed,” losing much of its biodiversity in the process.
Pesticides are not a modern invention. Ancient Sumerians used elemental sulfur to protect crops from insects, and medieval farmers and scientists experimented with chemicals like arsenic. Nineteenth-century research focused on compounds made from plants, including chrysanthemum. In 1939, dichlorodiphenyltrichloroethane, better known as DDT, was discovered to be extremely effective against both agricultural and disease-carrying insects. It rapidly became the most widely used insecticide in the world. Twenty plus years later, shortly after Rachel Carson’s Silent Spring shed light on the devastating effects of DDT on the environment, serious concerns about its impact on human and animal health led the US and 80 more countries to ban its use. The book also galvanized the environmental movement and the creation of the EPA, which is still responsible for monitoring pesticide use.2
As agriculture has grown and modernized, industrial agriculture has come to rely on pesticides for large-scale practices such as monocropping — growing one crop in great quantities, season after season, on the same land. Despite the widespread recognition that pesticides are harmful in a variety of ways, the continued rise of industrial agriculture depends on their use.
For farmers, pesticides are labor saving and generally provide a higher yield: it can mean the difference between saving a crop and losing it to disease. Some farmers, especially those who grow produce at a smaller scale, use pesticides sparingly as needed. For example, fruit trees are susceptible to disease in northeastern regions, especially at the blossom stage. An apple or peach grower may spray her fruit trees with a fungicide once in the spring to ensure that the fruit sets, but use no further chemicals for the rest of the season.
For many large row crop farmers, on the other hand, regular pesticide use is as much a part of farming as planting seeds. Spraying Roundup on a field of corn genetically engineered to withstand the chemical kills the weeds without affecting the corn. In comparison to mechanically weeding hundreds or thousands of acres, using pesticides is a game-changer. Some farmers spray their wheat with a weed-killer at the end of the season to kill the wheat itself and to speed its drying process. Farmers growing fruit or vegetables on a large scale, especially delicate varieties like strawberries, will blanket the field with pesticides to ward off any possible disease.
More than 90% of corn, soybeans and cotton in the US are genetically modified to be resistant to herbicides.
The carpet-bombing approach to pesticide use is a hard habit to break. Even while farms are increasingly industrialized, with growing plants fed by chemical fertilizer in sterile soil, a farm is still ultimately an ecosystem with complicated interrelationships among organisms. A dependence on pesticides has meant that generational knowledge of how to address weed or disease problems might no longer be passed down, which may leave farmers out of options if and when the chemicals fail. The many farmers using the GE seed/pesticide combination have invested a lot of money and time in that system, and there is no easy way to break out of that cycle.
The most recent report on pesticide sales and use from the US Environmental Protection Agency (EPA) puts US pesticide use at 1.1 billion pounds in both 2011 and 2012, which amounts to 23 percent of the nearly six billion pounds used worldwide. 3 Agriculture accounts for nearly 90 percent of pesticides in the US, with industry/commercial/government and home and garden use making up the rest.
Herbicides are the most common type of pesticide used, accounting for almost 90 percent of the pesticides used by the agriculture sector.4 Monsanto, the agrochemical company now owned by Bayer, is well known for having genetically engineered seeds to resist glyphosate, the active ingredient in its popular “Roundup” herbicide. The combination of these two products — herbicide-resistant seeds and accompanying herbicide — has allowed this suite of agricultural technologies to become almost universally used by large-scale farmers. 5 It has also led to a huge increase in Roundup application since it can be applied liberally without fear of killing crops. The total volume of glyphosate that was applied to the three largest, genetically engineered (GE) crops — corn, cotton and soybeans — increased tenfold , from 15 million pounds in 1996 to 159 million pounds in 2012. 6 The use of the GE herbicide-resistance technology keeps increasing, however, and more than 90 percent of corn, cotton and soybeans planted today are herbicide-resistant. 7
The agricultural chemical companies and their trade associations (with names like CropLife), motivated by profit, are highly invested in keeping farmers reliant on pesticides. Pesticides are a $14 billion industry in the US; two-thirds are for agricultural use. Most of those sales are herbicides paired with genetically modified seeds, but these numbers do not include sales of the seed itself. In 2017, Monsanto’s net sales of genetically engineered (GE) corn, soybean and cotton seeds and associated GE technologies totaled $9.5 billion. 8
As the industry has exploded, the companies involved have grown and merged. What had been six major agricultural chemical companies had, by 2018, merged into just three: DowDuPont, ChemChina and Syngenta and Bayer/Monsanto. 9 This much control concentrated in a few mega-corporations means fewer options for farmers, as well as higher prices — and increasing political power for the companies.
The agrochemical industry has been politically powerful for many years. 10 As a bloc, the agricultural inputs sector spent nearly $33 million in lobbying Congress in 2016. 11 The “revolving door,” by which former industry leaders serve in the government agencies overseeing their industries, is well-used by agribusiness, mainly to keep regulation of pesticides and other agricultural products and practices extremely limited. 121314
Research, as well, has been a victim of the powerful pesticide industry: as public spending on agricultural research and development has been cut precipitously, industry now funds a much larger share. 1516 This means that they may decide not to investigate certain issues or may withhold results that are unfavorable to their products. 17
The outcry following the publication of the 1962 book Silent Spring — which documented the detrimental environmental effects of overuse of pesticides — resulted in DDT being banned in the US and created an awareness of the hazards of other pesticides. But unsafe herbicides, insecticides and fungicides continue to be used on fields at extraordinary rates. These chemicals have been shown to have horrible effects on those who administer them or come into contact with them throughout the production and supply chain. In addition, whether or not eating food with pesticide residues is unsafe is still inconclusive, but of concern for many public health advocates.
Pesticides are assessed by the Environmental Protection Agency for risks posed to ecosystems, human health and cumulative toxic effects. The EPA also establishes tolerances, or amounts allowed on or in a food, for each pesticide. 18 The US Food and Drug Administration (FDA) and USDA annually survey and publish information regarding pesticide residues in the food supply. 1920 However, many EPA-designated tolerance levels are outdated and may not fully account for a range of health risks, such as hormone (or, endocrine) disruption. 21 Moreover, the risks assessed by the FDA and USDA do not include cancer, despite the fact that many pesticides have been implicated as carcinogens.
Even if low use of some pesticides is regarded as safe for humans or the environment, safety studies may not accurately account for real-life exposure to many different chemicals over a lifetime. In fact, some studies have shown that long-term, intensive exposure does have adverse effects.
One 2011 meta-study of common endocrine disrupter pesticides, for example, showed that both wildlife and certain human populations were negatively impacted in significant ways. 22 In infants and children, as well as people who live or work in agricultural areas, endocrine disruptors have been linked to low birthweight, abnormal brain development, increased incidence of cancers, reduced male fertility among other issues. 23
Additionally, a 2010 report by the President’s Cancer Panel concluded that pesticides were associated with numerous types of cancers, including brain, pancreatic, non-Hodgkin lymphoma, myeloma, colon, testicular and soft tissue sarcoma. 24
There is some debate about possible cancer risks of glyphosate, the main ingredient in Roundup, the world’s most widely used herbicide. In 2015, the World Health Organization analyzed the existing research on glyphosate and came to the conclusion that glyphosate could be a carcinogen, having found some evidence of an increased prevalence for non-Hodgkin lymphoma after glyphosate exposure. 25 In the following few years, the US EPA and the UN Food and Agriculture Organization undertook a similar analysis incorporating data from additional studies that hadn’t been included in the WHO analysis, and declared glyphosate as unlikely to be a carcinogen. 26 It’s worth noting, however, that the EPA opted to include unpublished data that was provided directly from Monsanto itself, which was excluded by WHO’s standard of only using publicly available data. 27
While additional studies will be needed to determine whether glyphosate is carcinogenic, and at what levels of exposure, a number of lawsuits related to the issue have been proceeding. Recently, several court cases have found Monsanto liable for damages to people saying the company’s glyphosate-based weed-killers made them lethally ill after prolonged exposure, and there are thousands of similar lawsuits in progress. 28
Another pesticide gaining national attention is chlorpyrifos. Exposure to chlorpyrifos can be harmful to brain function and is associated with preterm births and neurological disorders. Studies have concluded that the pesticide is dangerous to children, even in utero. 2930 Given the magnitude of evidence showing the impact to human health, and the decision of the EPA to delay banning the pesticide, three US states — New York, California and Hawai’i — have banned use of chlorpyrifos. 31
While USDA testing consistently finds that nearly all food samples have pesticide residues, the levels are well below the tolerance levels established by the EPA. These studies show that multiple, different residues are frequently found on any given produce item, the consequences of which are not yet understood. 32 Follow-up analysis by the Environmental Working Group (EWG) has instead shown that 70 percent of samples were contaminated with pesticide residues but cautions that there are stark differences in amounts of residue based on the kind of produce sampled, depending on factors like whether or not it has a thick peel, and also which pesticides are applied and how. 33 EWG’s annual Dirty Dozen and Clean Fifteen lists provide details about the most and least contaminated, which should guide consumers on which products to prioritize when considering buying organic.
Eating a diet containing lots of produce an important part of a healthy diet. However, limiting exposure to and ingestion of pesticides should be the next priority. Generally, the less exposure to pesticides over a lifetime the better.
Pesticide that is sprayed on crops leaves a residue on the dead plant material that settles into the soil and can run off into waterways or leach into groundwater. A 2014 study performing tests across 38 states found glyphosate in the majority of rivers, streams, ditches and wastewater treatment plants, as well as in 70 percent of rainfall samples. 34 Even at levels deemed safe, pesticides have been shown to cause a loss of biodiversity, including reduced numbers of beneficial insects, as well as birds and amphibians. 35 The EPA maintains a list of the potential effects of pesticides on aquatic life and other animals as a reference for researchers investigating water quality. 36
While farmers use pesticides to increase crop yields, many of the starkest problems caused by pesticides are most evident on the farm.
Evidence is rapidly growing that several classes of pesticides are implicated in pollinator decline, including honeybee colony collapse disorder. Vegetable, fruit and nut farmers rely on insect and small mammal pollinators; even self- or wind-pollinated row crops like corn and soybeans have better yields when a healthy population of pollinators is present. Neonicotinoid pesticides are conclusively linked to widespread honeybee decline, with recent evidence showing traces of those and other pesticides in a large sample of local honey from around the world. 37
A more obvious problem for farmers is pesticide resistance and the development of “superweeds.” Over time, some weeds that have been exposed to glyphosate adapt to survive the herbicide. These weeds then reproduce, passing their ability to resist the herbicide to the next generation of weeds. Herbicide resistance is increasingly common, and some areas may have multiple herbicide-resistant weed species in their fields, making weed control even more difficult. 38 In just the US, scientists have already discovered 25 species of weeds that have grown resistant to herbicides. 39
Chemical companies like Monsanto and Dow are heavily invested in their seed technology — seeds genetically modified to resist herbicides — which means that they are tied to herbicides as well. If weeds develop resistance to one chemical, the industry solution is to combine it with an older, more toxic chemical Thus 2,4-D has been approved by the EPA in combination with glyphosate. The new use of 2,4-D is expected to lead to a 300 to 700 percent increase in the chemical’s use by 2020. 40
Another older herbicide, dicamba, which was previously approved only for ground spreading, was EPA-approved in 2017 for aerial spraying in conjunction with soybean seeds genetically engineered to be resistant to the chemical. Dicamba is extremely volatile: during spraying, it can turn back into gas and drift several miles, killing or damaging any plant material wherever it lands — which in this case could be on practically any plants aside from protected GE soybeans. 41
Crop-damaging pesticide drift can ruin a neighboring farm’s organic certification. Dicamba is prone to pesticide drift, even when applied according to label instructions. If a farmer chooses not to grow pesticide resistant crops and a neighboring farm’s pesticide drifts over, it can damage or ruin that farmer’s crop, causing bitter conflict among farming communities. 42 In 2017, damage from dicamba drift was reported in 25 states, mostly to non-GE soybeans, but also to vegetables, fruits, vineyards and trees. 43 Rather than rejecting this damaging chemical altogether and sanctioning the seed and chemical manufacturer for bad practices, the soybean growers decided instead to plant dicamba-resistant seeds; this has further expanded the use of the herbicide, benefiting the bottom line of the seed and chemical manufacturer, and also increasing the possibilities of dicamba drift.
Reducing or eliminating pesticide use means turning instead to ecosystem management, using crop rotations and investment in soil health to build a population of beneficial microorganisms, insects and plants that will do the work of warding off diseases and weeds. There are many ways to do this and even a reduction in pesticide use can have huge benefits. A 2012 Iowa study, for example, found that simply adding an additional crop such as oats into the common rotation of corn and soybeans allowed farmers to use far less herbicide for weed control and to dramatically cut water contamination, while maintaining similar yields. 44
Integrated Pest Management (IPM) embraces a continuum of practices among farms of all sizes, beginning with identifying pests before spraying. For instance, an IPM farm may grow pest-resistant crop varieties, use predatory insects to kill plant-eating pests, employ mechanical pest traps and eliminate pest nesting areas by plowing under harvested crops. 45 If further control is needed, IPM farmers would employ a targeted approach, using broadcast spraying only as a last resort.
Other techniques used by sustainable farms to reduce the need for pesticides include crop rotation, cover cropping, spring weed management, deciding whether to till the soil and when, deciding when to plant the harvest crop and other methods to disrupt the pest life cycle.
Farming that does not rely on chemical pesticides requires more specialized knowledge, time and labor on the part of the farmer; thus, the products are often more expensive. As a consumer, if you can afford the extra cost, you are making an investment in a healthier agricultural system for everyone. Purchase organic and sustainably produced foods at your local farmers’ markets or farms, where you can ask the farmer directly about his or her pest control methods.