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Featured Turfgrass Article The Glyphosate Debacle *Previously Printed in TPI
Travis W. Gannon, PhD NC State University
The 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. Despite granted patents and research for various uses, glyphosate has been used exclusively as an herbicide for over four decades. Glyphosate is a highly efficacious, nonselective herbicide that was commercially released in 1974 in the United States. While Roundup is most commonly associated with glyphosate, it is currently sold under numerous trade names, is registered in over 100 countries, and 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. Further, 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. Glyphosate controls susceptible plants by inhibiting the enzyme 5-enolpyrivylshikimate 3-phosphate synthase that causes a shortage of essential amino acids required for plant growth. Where are we today?
The issue: There 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, it’s heightened recently specifically around glyphosate and has created bounteous fear among the public sector. Why? There 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. The 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.