In 1997 there were 432 new patents for herbicides, by 2009 there were only 65. The development of broad spectrum glyphosate and “Roundup Ready crops” was a game changer that worked so well people basically stopped looking for new herbicides. That is until the weeds started fighting back.

Chemical & Engineering News article on the search for new modes of action
https://cen.acs.org/environment/pesticides/crop-protection-herbicide-mode-action-glyphosate/100/i22

Introduction to the Shikimate Pathway
https://www.youtube.com/watch?v=FlBrJW-qbXA&list=PL833687AEAAE90961&index=155

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Executive Producer:
Matthew Radcliff

Producers:
Elaine Seward
Andrew Sobey
Darren Weaver

Host:
Alex Dainis

Scientific Consultants:
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Patrick J. Tranel, PhD
Todd Gaines, PhD
Mithila Jugulam, Ph.D.
Leila Duman, PhD
Brianne Raccor, PhD

Executive in Charge for PBS: Maribel Lopez
Director of Programming for PBS: Gabrielle Ewing
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Reactions is a production of the American Chemical Society.
© 2022 American Chemical Society. All rights reserved.

Additional Sources:
Molecular basis for the herbicide resistance of Roundup Ready crops
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1559744/

THE SHIKIMATE PATHWAY
https://www.annualreviews.org/doi/10.1146/annurev.arplant.50.1.473

Why have no new herbicide modes of action appeared in recent years?
https://onlinelibrary.wiley.com/doi/10.1002/ps.2333

The Pitfalls of Relating Weeds, Herbicide Use, and Crop Yield: Don’t Fall Into the Trap! A Critical Review
https://www.frontiersin.org/articles/10.3389/fagro.2020.615470/full

The cost of herbicide resistance
https://crops.extension.iastate.edu/blog/bob-hartzler/cost-herbicide-resistance

Development and Characterization of a CP4 EPSPS-Based, Glyphosate-Tolerant Corn Event
https://web.archive.org/web/20090319094255/http://crop.scijournals.org/cgi/content/abstract/45/1/329?ijkey=44fad6f377d5b5dfe274484eb51a4c79d0d7ff63&keytype2=tf_ipsecsha

Tyrosine Biosynthesis, Metabolism, and Catabolism in Plants
https://bit.ly/3CsMiiS

Biosynthesis and Metabolic Fate of Phenylalanine in Conifers
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4942462/

Auxin driven indoleamine biosynthesis and the role of tryptophan as an inductive signal in Hypericum perforatum (L.)
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6797091/

Finding of No Significant Impact
Animal and Plant Health Inspection Service
Petition for Non-regulated Status for Soybean Line MON 89788 (APHIS 06-178-01p)
https://www.aphis.usda.gov/brs/aphisdocs/06_17801p_ea.pdf

Glyphosate resistance: state of knowledge
https://onlinelibrary.wiley.com/doi/pdf/10.1002/ps.3743