Chapter 17: MOA Part 3: Growth Regulators (Auxinic Herbicides)

Disclaimer:

The information and suggestions in this publication are intended to provide general guidelines for weed management in Ohio. Because of changing laws and regulations, Ohio State University Extension assumes no liability for the recommendations. The recommendations for using pesticides included in this guide are incomplete and should not serve as a substitute for pesticide labels. Complete instructions for the use of a specific pesticide are on the pesticide label. The pesticide user is responsible for applying pesticides according to label directions, as well as for problems that may arise through misapplication or misuse of the pesticide. Label changes, product cancellations, and changes in recommendations may have occurred since the publication of this guide. Check with your county Extension agent in agriculture if you are in doubt about a pesticide you plan to use. Trade names have been used in this guide for clarity, but do not constitute an endorsement by The Ohio State University, nor do they imply discrimination against other products.

Copyright 2018

Chapter Authors

Dr. Deana Namuth-Covert, Professor and Ms. Amy Kohmetscher, Instructional Designer

Ohio State – Agricultural Technical Institute

College of Food, Agricultural and Environmental Sciences

The Ohio State University

Select materials in this chapter are utilized and updated from:

Sterling, T. and Namuth, D. (2004) Auxin and Auxinic Herbicide Mechanism(s) of Action – Part 1 – Introduction http://passel.unl.edu/pages/informationmodule.php?idinformationmodule=1022008824

The selective control of broadleaf weeds in cereal grain crops by auxinic herbicides has made this group one of the most widespread and important herbicide families used in crop production. These herbicides are thought to act as hormone mimics. They were the first herbicides developed that were selective or able to kill one group of plants, but not another (i.e. kill broadleaf, but not grass plants). This chapter will introduce the key features of these herbicides, discuss their major uses and describe the injury symptoms they cause as well as how they kill sensitive plants.  Resistance to these herbicides will also be discussed.