Stop Spraying Poison on Our Food Before Harvest
For generations, American farmers grew wheat, oats, soybeans, and other food crops, allowed them to mature, and harvested them without spraying herbicides over the fields shortly before bringing the crops into the food supply
They relied on natural maturation, field drying, swathing, and mechanical harvesting. These methods were not primitive relics of an agricultural past.
They were practical techniques that helped feed a growing nation, and many remain in use today. In fact, organic farmers still routinely use these methods to dry crops prior to processing.
Then came another agricultural innovation, one that promised farmers greater convenience, more predictable harvest schedules, and potentially lower operating costs. Instead of waiting for crops to dry naturally, farmers could apply chemical herbicides shortly before harvest to kill remaining green vegetation, accelerate drying, or make harvesting more uniform.
The practice is called preharvest chemical desiccation. Glyphosate, the active ingredient historically associated with Roundup, is among the chemicals used for this purpose. Others include paraquat, diquat, sodium chlorate, saflufenacil, and carfentrazone, depending on the crop and the product’s regulatory approval.
What began as a specialized agricultural technique has become an established harvest-management practice in American agriculture. Yet the American public has received remarkably little information about how frequently these chemicals are applied immediately before food crops are harvested, what residues remain, or whether the benefits justify the additional chemical exposure.
This all needs to change.
This is not an argument for eliminating all herbicides from American agriculture at this point in time. Nor is it an argument about genetically modified crops, conventional weed management, or the use of herbicides to terminate cover crops before planting. Those are separate issues.
This is about one specific practice: spraying herbicides onto crops shortly before harvesting them for food.
It is an agricultural practice we can reconsider and phase out without reinventing farming.
How Did This Become Normal?
Chemical crop desiccation became normalized during the 1980s and 1990s, when preharvest glyphosate applications became established in certain grain-producing regions. Charles Benbrook’s 2016 peer-reviewed analysis, Trends in Glyphosate Herbicide Use in the United States and Globally, identified increasing harvest-aid applications beginning in the mid-2000s, particularly involving wheat, barley, edible beans, and other crops in northern states.
The growth of glyphosate use overall was extraordinary. Estimated U.S. agricultural use increased from approximately 7.7 million pounds of active ingredient in 1990 to nearly 250 million pounds in 2014, an increase of more than thirtyfold.
Not all of that increase involves preharvest desiccation. Much of glyphosate use is associated with weed management, including the adoption of glyphosate-tolerant crops. It would be inaccurate to attribute the entire increase to spraying immediately before harvest.
Nevertheless, the expansion of preharvest applications was part of a larger transformation in American agriculture, one in which chemical intervention increasingly replaced traditional management practices.
There is a revealing gap in the federal data. USDA surveys report how many acres receive particular herbicides, how much is applied, and which crops are treated. But the publicly available national summaries do not consistently distinguish preharvest applications from herbicide treatments earlier in the growing season.
Consequently, we cannot confidently state what percentage of American wheat, oats, or soybeans receives preharvest chemical desiccation in any given year.
That is not a minor omission. It means the public cannot easily determine how widespread the practice has become, despite its potential implications for food residues and environmental exposure.
And it raises an obvious question: Why isn’t USDA routinely publishing those numbers?
These Chemicals Are Applied When Food Is Nearly Ready to Harvest
The timing is what makes preharvest desiccation different from many other agricultural pesticide applications.
When herbicides are applied earlier in the growing season, there may be weeks or months before harvest. Environmental degradation, plant metabolism, and dew and rainwater runoff that remove or dilute the chemicals can affect the eventual residue concentrations.
Preharvest applications are left on the crop.
For example, some EPA-approved glyphosate labels permit applications to mature wheat with a minimum interval of seven days before harvest. Glyphosate may be applied to a standing food crop approximately one week before it enters the harvesting process.
Glyphosate is a systemic herbicide. It can be absorbed by plants and transported through their tissues. Consequently, residues cannot necessarily be eliminated by rainfall, washing, or removing material from the surface of the grain just prior to harvest.
Other herbicides have different chemical properties, environmental behavior, and residue profiles. Paraquat and diquat are contact herbicides, while sodium chlorate and saflufenacil operate through different mechanisms. Their risks cannot simply be assumed to be identical to glyphosate’s.
But the common question remains: Why apply these chemicals to food crops at the very end of their growing cycle when the primary benefit is often harvest management rather than increased biological production?
A mature wheat plant does not produce additional grain because it has been sprayed with glyphosate. In other words, these chemicals are not indispensable to producing the crop. They are tools used to manage the harvest.
That distinction should be central to any serious regulatory assessment.
Americans Are Excreting Glyphosate
In 2022, the CDC published biomonitoring findings showing that glyphosate was detectable in the urine of approximately 81 percent of Americans represented by its 2013–2014 National Health and Nutrition Examination Survey samples.
This means that exposure was widespread enough for the chemical to be detected in urine using modern analytical methods.
Glyphosate was not part of American agricultural practice before its commercial introduction in the 1970s. Today, measurable exposure is common.
Urinary measurements do not identify what fraction of exposure results specifically from preharvest desiccation. Nevertheless, preharvest applications represent an identifiable exposure pathway that can be investigated and potentially eliminated.
And glyphosate is not the only chemical involved.
Other preharvest herbicides may leave residues in harvested commodities, depending on their application rates, chemical properties, crop metabolism, and time between treatment and harvest.
The Regulatory Question EPA Has Not Adequately Answered
Under federal pesticide law, the EPA establishes residue tolerances using toxicological assessments, residue studies, estimated dietary exposure, and other evidence. These tolerances determine the maximum concentrations legally permitted in or on food.
Over time, some glyphosate tolerances have increased substantially.
For example, the tolerance for glyphosate residues in wheat grain increased from five parts per million in 2000 to 30 parts per million under the current regulation. The tolerance for oat grain increased from 20 to 30 parts per million, while the tolerance for field corn grain increased from one to five parts per million.
These are legal maximum concentrations, not measurements of typical residues in supermarket foods. Nor can every increase automatically be attributed to preharvest desiccation. Some changes reflect other registered agricultural uses.
But the regulatory history raises an important question. When EPA evaluates a proposed preharvest application, it asks whether residues resulting from the authorized use can be considered safe under its established toxicological and dietary exposure framework.
What is less clear is whether EPA has systematically compared the dietary exposure resulting from preharvest desiccation against the exposure that would occur if the same crop were harvested without chemical treatment.
That is the comparison that matters for this policy question. If wheat, oats, soybeans, or other food crops can be harvested without a late-season herbicide application, then the relevant question should not be limited to whether the resulting residues fall below an established regulatory ceiling.
It should also be whether the additional chemical exposure is necessary. A tolerance is permission for a certain level of residue. It is not proof that the residue was unavoidable.
Exposure to these chemicals needs to be limited in every way possible. Instead, the EPA sets exposure limits and walks away from the issue.
The Scientific Literature Is Raising Questions
For years, the debate over glyphosate has been dominated by arguments about carcinogenicity, particularly the disagreement between the International Agency for Research on Cancer and regulatory agencies that have reached different conclusions about cancer risks under evaluated exposure conditions.
But the research literature extends far beyond cancer.
Experimental studies have examined glyphosate and glyphosate-based formulations in relation to reproductive development, endocrine signaling, oxidative stress, the intestinal microbiome, neurological development, and other biological systems.
A 2022 study by Gerona and colleagues detected glyphosate in the urine of 186 of 187 pregnant women enrolled in a high-risk Indiana pregnancy cohort. Among the pregnancies included in the outcome analysis, higher first-trimester urinary glyphosate concentrations were associated with lower birth-weight percentiles.
A separate study by Lesseur and colleagues detected glyphosate and its degradation product AMPA in most maternal urine samples from a smaller multicenter pregnancy cohort. The investigators reported associations involving AMPA and anogenital distance in female infants, although some glyphosate associations did not remain statistically significant after adjustment.
These are observational studies. They cannot establish that glyphosate caused the outcomes, and they cannot identify preharvest spraying as the source of exposure.
Animal experiments provide additional mechanistic evidence. Studies have reported changes in ovarian steroidogenesis, sperm development, reproductive tissue structure, and endocrine signaling following glyphosate or glyphosate-based herbicide exposure.
A 2024 mouse study by Valente and colleagues found that mixtures of glyphosate and 2,4-D worsened certain reproductive abnormalities associated with a Western-style diet.
The exposure levels, formulations, and experimental conditions differ substantially among these studies. Some are relevant to low-dose exposure; others involve concentrations that cannot be directly equated with ordinary dietary residues.
Recent reviews published in 2025 have continued examining reproductive toxicity, endocrine effects, environmental contamination, and the potential importance of formulation ingredients that are not captured by testing glyphosate alone.
This growing literature is relevant to regulatory decisions because pesticide approvals necessarily involve judgments about uncertainty, exposure, and acceptable risk.
If a particular exposure pathway is not essential to producing food, the case for allowing it deserves renewed scrutiny.
The data on urine GLY concentration and nine health outcomes, including type 2 diabetes mellitus (T2DM), hypertension, cardiovascular disease (CVD), obesity, chronic kidney disease (CKD), hepatic steatosis, cancers, chronic obstructive pulmonary disease (COPD), and neurodegenerative diseases (NGDs), were extracted from NHANES (2013-2016)
The findings of the study revealed that individuals with higher urinary concentrations of GLY had a higher likelihood of having T2DM (type 2 diabetes), hypertension, CVD and obesity (p < 0.001, p = 0.005, p < 0.001 and p = 0.005, respectively). In the reverse-scale Cox regression, a notable association was solely discerned between exposure to GLY and the risk of T2DM (adjusted HR = 1.22, 95 percent CI: 1.10, 1.36).
Consistent outcomes were also obtained via logistic regression analysis, wherein the adjusted OR and 95 percent CI for T2DM were determined to be 1.30 (1.12, 1.52). Moreover, the present investigation identified serum high-density lipoprotein cholesterol (HDL) as a mediator in this association, with a mediating effect of 7.14 percent (p = 0.040). This mediating effect was further substantiated by RCS regression, wherein significant dose-response associations were observed between GLY exposure and an increased risk of T2DM (p = 0.002) and reduced levels of HDL (p = 0.001). Collectively, these findings imply an association between GLY exposure and an increased risk of T2DM in the general adult population.
The Environmental Damage Done
Food residues are only part of the story. Herbicides can move beyond the treated crop through runoff, drainage, erosion, and spray drift.
USGS monitoring has documented glyphosate in American streams and rivers. EPA ecological assessments have identified potential risks to nontarget plants and animals from several herbicides used in agriculture, including paraquat and diquat.
Aquatic plants and algae can be especially vulnerable to herbicides because the chemicals are designed to interfere with plant growth or survival. Some herbicides and formulations also affect aquatic invertebrates, fish, amphibians, and other organisms.
Healthy soil is not simply a medium that holds plant roots. It is a living ecosystem containing fungi, bacteria, protozoa, nematodes, earthworms, and countless other organisms involved in decomposition, nutrient cycling, and plant health.
Research has demonstrated that glyphosate exposure can alter soil microbial communities and biological processes. Agricultural chemicals do not necessarily remain confined to their intended targets, and repeated exposures can influence ecosystems in ways that extend beyond the immediate agricultural purpose and are difficult to measure.
There are also indirect effects. Herbicide-driven removal of vegetation can reduce habitat and food resources for insects and other invertebrates, with potential consequences for birds and other wildlife that depend on them.
Every unnecessary application adds to the overall chemical burden that agriculture places on the environment.
Eliminating routine preharvest applications would remove one identifiable source of that burden.
This is taken from a long document. Read the rest here malone.news
Italic emphasis added