THE GLYPHOSATE DEBACLE By Travis W. Gannon, PhD
Te herbicide glyphosate has permeated news outlets in recent months. Unfortunately, much of the disseminated information has been misconstrued and/or contains misinformation. While this has and will continue to impact various facets of agriculture including sod production, it’s important to understand why glyphosate appears to be “under attack” as it affects the future of the industry.
Brief history Glyphosate was first synthesized in 1950 by a Swiss chemist but was abandoned when no pharmaceutical applications were discovered. Several patents were issued for glyphosate in later years for various uses including metal chelating and descaling agent, antiparasitic agent, and therapeutic treatment of various pathogenic infections. Oddly enough as it relates to the current discussion, a patent was also submitted for glyphosate in 1995 as an “anti-cancer compound (U.S. Patent No. 5665713 A)” as researchers reported the compound inhibited the growth of cancers and tumors in mammals. Procter and Gamble Co. applied for and was granted the patent in 1997. Despite other patents and research for various uses, glyphosate has been used exclusively as an herbicide for over four decades.
Glyphosate is a highly effective, nonselective herbicide that was commercially released in 1974 in the United States. While glyphosate is most commonly associated with Roundup, it is currently sold under numerous trade names, is registered in over 100 countries, and is available in over 750 commercially available products. Glyphosate is registered in various use sites including sod production, golf courses, athletic fields, commercial and residential lawns, rights of way, forestry, industrial sites, as well as many agronomic cropping systems including glyphosate tolerant cropping systems. Furthermore, glyphosate is the most commonly applied herbicide across agricultural commodities.
As previously mentioned, glyphosate is a nonselective herbicide which controls numerous annual, biennial, and perennial grass and broadleaf species. It does this by inhibiting the enzyme 5-enolpyrivylshikimate 3-phosphate synthase, which subsequently causes a shortage of essential amino acids required for plant growth.
Where are we today? Te issue: Tere is much scrutiny around pesticide use in many sectors of society today including sod production and other turfgrass systems. While this is not a recent development, the heightened discussions around glyphosate have created fear among some within the public sector.
Why? Tere are many complex factors that have led to the issues around glyphosate today, some of which will be discussed in this article. Fundamentally, there is a divergence in opinion about the human carcinogenicity of glyphosate. Te International Agency for Research on Cancer (IARC) classified glyphosate as a Group 2A probable carcinogen in March 2015. We will walk through other agencies’ conclusions from around the world and attempt to explain why IARC stands alone in their classification. We will also identify the agencies and their roles and will include respective agencies quoted conclusions from comprehensive assessments. It is also important to note we will focus on environmental and food safety agencies; however, special interest groups have been active in this situation and their actions influence much of what is occurring today.
What’s the specific problem with glyphosate? With one agency classifying glyphosate as a Group 2A probable carcinogen, there has been much misinformation spread about glyphosate as well as other pesticides. Tis has resulted in a cascade effect including lawsuits against Bayer; bans on glyphosate in countries, cities, municipalities and counties; product distributors no longer willing to sell glyphosate due to preference or insurance requirements; and other unwarranted actions.
An over-arching view of the position statements of various agencies regarding the human carcinogenicity of glyphosate is captured below as well as in Table 1.
European Food Safety Authority (EFSA). Te EFSA is a European agency funded by the European Union to provide scientific advice and communication on risks associated with the food chain. Te EFSA was established in 2002 after a series of food crises in the late 1990s and is headquartered in Parma, Italy. Teir position states: “Following a second mandate from the European Commission to consider the findings from the International Agency for Research on Cancer (IARC) regarding the potential carcinogenicity of glyphosate or glyphosate-containing plant protection products in the on-going peer review of the active substance, EFSA concluded that glyphosate is unlikely to pose a carcinogenic hazard to humans and the evidence does not support classification with regard to its carcinogenic potential according to Regulation (EC) No 1272/2008.” (2015)
Health Canada. Health Canada is a regulatory agency that protects Canadian’s health and their environment through rigorous science-based assessments. Health Canada was established in 1993 and is headquartered in Ottawa, Canada. Teir position states: “Glyphosate is not genotoxic and is unlikely to pose a human cancer risk.” (2017)
48 TPI Turf News September/October 2019
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