An Open Letter to AAAS Science Magazine from members of the SeTA (Science and Technology for Agriculture, network.


In a recent letter to Science, Peng et al. (2020)[1] argue that the USA and the European Union (EU) should enact a total ban on glyphosate on the grounds that it causes “a cascade of neuro-endocrine disruption to the development, physiology, and behaviour of honeybees” and that “some evidence has indicated that glyphosate could promote (sic) cancer in humans”. Consequently, they call for “natural and ecological weedkilling alternatives and less intensive farming practices”.

The authors cherry-pick references, some of them being second-handed (e.g.: # 1, 3, 8, 9, 10), to support their statements, and pay little attention to the need of making assessments under real-life conditions of exposure for both humans and wild-life. The few original scientific papers that are quoted (# 4, 5, 6) have little indication that the experimental conditions resemble real life wild animals exposure, and have not been independently replicated.

There is an almost complete consensus by the governmental regulatory bodies in the world (see e.g. EPA[2], EChA[3], EFSA[4], FAO/WHO JMPR[5])  that glyphosate does not harm human health. Only IARC (2015)[6] claimed that glyphosate is probably carcinogenic to humans while EPA warned against labeling glyphosate containing products as carcinogenic (EPA 2019)[7]. Hence, there is no ground to call for a ban of glyphosate because of its carcinogenicity despite a vocal media campaign in this respect, which should not be part of a scientific debate; see their reference #8 which is from an activists’ association. Unless we want, as their reference #1 proposes, that regulatory decisions are based on ordeal rather than science.

In conclusion, the call for the ban of glyphosate is unsubstantiated because its use appears safe for humans and wildlife if applied appropriately according to the approved indication. Moreover, its ban will have both economic and environmental negative consequences to agriculture[8], including the possibility of either abandonment of conservation agriculture, a practice strongly promoted worldwide to improve soil and water quality, or the application of less effective and more expensive chemical and non-chemical means[9].  Other approaches suggested by Peng et al., such as “root exudates…, crop rotation, mulch, herbicidal soaps, fatty acids, and industrial vinegar” look currently more a wishful thinking than a real alternative, as indeed suggested by their reference #11.

As side notes we would like to point out that Peng et al. confuse herbicides such glyphosate with insecticides such as DDT and parathion which, acting on the nervous system, under uncontrolled exposures cause harm to humans. Therefore, glyphosate cannot be an “alternative” to DDT and parathion as stated. Moreover, reference #11 is misreported, since the first, and not the last, names of the authors are given, and reference #3 is misquoted since it does not report on human toxicity of either glyphosate or insecticides; rather, it hints that glyphosate may be more ecologically sustainable than its alternatives, a correct statement for us.


Angelo Moretto

Department of Biomedical and Clinical Sciences

Università degli Studi di Milano

International Centre for Pesticides and Health Risks Prevention

Luigi Sacco Hospital, Milano, Italy

Vittoria Brambilla

Department of Agricultural and Environmental Sciences

Università degli Studi di Milano, Italy

Roberto Defez

IBBR-CNR, Napoli, Italy

Aldo Ferrero

Department of Agricultural, Forest and Food Sciences

Università degli Studi di Torino, Italy

Donatello Sandroni

Giornalismo & Comunicazione

Crotta d'Adda (CR), Italy

All authors are member of the SeTA (Science and Technology for Agriculture, network.

[1] Peng W et al. Science 367 (6475), 257 (2020)







[8] H. Kehlenbeck, et al. Julius-Kühn-Archiv 451 (2019), ISBN: 2199-921X

[9] Pardo G., Martinez Y. Planta Daninha 37, (2019)

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