Pesticides have brought humans breathtaking benefits. They help to protect plants from the adverse impact of weeds, parasites and microscopic pathogens that is a constant threat to their existence. Pesticides were vital for the Green Revolution (occurring between the 1930s to 1960s). This was a powerful transformation that doubled to tripled agricultural output and is credited with saving the lives of hundreds of millions of people from starvation. If pests were allowed to reign free, an estimated 50% to 80% of all crops (ranging from wheat to cotton) would be lost (Oerke, 2006), although pesticides are not the only form of crop protection available. Pesticides can also suppress insect vectors for important human diseases and reduce the amount of exhausting manual labor used to clear weeds.
Yet, there is a much darker side to pesticides that cannot be ignored. Large, chronic occupational exposure to pesticides can make people sick or even kill them. Pesticides are typically very broad in their specificity, so they do not just harm the target pest, but many non-target organisms that benefit both the crops and the environment. They can also contaminate surface water, ground water and soil and thus have much more far-reaching effects on organisms outside the field. Excessive agricultural use can also make pests resistant to the pesticides, which can substantially reduce their effectiveness in managing insect vectors for human diseases. Many pesticide apologists ignore or downplay many of these problems.
Developing newer and safer pesticides, replacing older and more harmful pesticides, and deploying biotechnology to help plants resist pests should be a global agricultural priority. Yet in a cruel twist, these crucial solutions are often opposed by many anti-pesticide activists and other extreme environmentalists who push fear and misinformation about “chemicals” and genetically modified crops. This apparent paradoxical situation might be called the perils of anti-pesticide hysteria.
Peril #1: Impeding development and use of safer pesticides.
Glyphosate is a herbicide that is much safer than many other herbicides. It targets the enzyme 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) that is involved in the Shikimate pathway for synthesizing the aromatic amino acids tyrosine, tryptophan and phenylalanine. Humans and other animals get these amino acids through food so it has no affect on the availability of those amino acids in those organism groups.
A 2015 report from the European Food Safety Authority (EFSA) concluded that the evidence shows that glyphosate probably does not damage DNA or cause cancer in humans (EFSA, 2015; EFSA, 2016). An earlier report from the WHO group International Agency for Research on Cancer (IARC) had claimed that glyphosate was probably carcinogenic in humans (Guyton et al, 2015), but this was contradicted by not only the previously mentioned EFSA report, but also by a joint WHO/FAO report that concluded that dietary exposure to glyphosate probably does not cause cancer (JMPR, 2016). IARC is not involved in risk assessment and ignores dose considerations.
Because glyphosate can replace much more harmful pesticides, it should be a welcome addition as a way of reducing the harms from pesticides. However, many anti-pesticide activists have specifically targeted glyphosate for a massive misinformation campaign. This is likely because it ties into crops that have been genetically modified to be resistant to glyphosate that are sold by the large agricultural biotechnology company Monsanto. Many extreme environmentalists oppose large corporations and most things associated with them, including GMOs and glyphosate.
Peril #2: Opposing GMOs that reduce reliance on pesticides.
Genetic modification is a set of important biotechnology method that can make small and highly precise modifications to the genome of plants that are exceptionally well-known. This can involve making the plant produce its own highly specific pesticide that only affects one group of pests (Bt crops) or boost the plants own defenses against viral infections (e.g. papaya resistant to PRSV).
Both of these examples results in a reduced reliance on pesticides. Yet many extreme environmentalists are strongly opposed to GMOs, despite the fact that they can have beneficial consequences for the struggle against harmful pesticides. This rabid rejection of GMOs is not well thought out and extraordinarily counterproductive. Environmentalists should celebrate GMOs that reduce the use of harmful pesticides, not demonize them.
Peril #3: Fearmongering about “chemicals”
In science, a “chemical” is merely a chemical substance. Both water and industrial bleach are chemicals. It makes no difference where the substance come from or how it is made. If it is a chemical substance, it is a chemical. In layman’s terms, “chemical” typically refers to something that is artificial and harmful.
Many anti-pesticide activists poison the language and create fear about many substances that are safe and effective simply because it has a complicated chemical name that is difficult to pronounce. This muddles the conversation with misinformation and unnecessary diversions.
In an ironic twist, many extreme environmentalists hinder efforts to reduce reliance on more harmful pesticides by opposing development and use of safer pesticides, spreading misinformation about GMOs and fearmonger about “chemicals”. They should at the very least understand risk assessment and get onboard with genetically modified crops that are found to be safe and effective.
References and further reading
EFSA. (2015). Conclusion on the peer review of the pesticide risk assessment of the active substance glyphosate. EFSA Journal. 13(11). 4302. Accessed: 2017-03-08.
JMPR. (2016). Joint FAO/WHO metting on pesticide residues: Summary report (cache). Accessed: 2017-03-08.
Oerke, E. (2006). Crop losses to pests. The Journal of Agricultural Science. 144(1). 31-43.
Guyton, K. Z. et al. (2015). Carcinogenicity of tetrachlorvinphos, parathion, malathion, diazinon, and glyphosate. The Lancet Oncology. 16(5). 490-491.