Herbicide Families and Modes of Action

Welcome to this CEU on Herbicide Families and Modes of Action. The purpose of this recertification CEU is to be used as an essential information source for understanding how each major herbicide group kills a plant, what it controls, and how it behaves in the field. As such, attention must be given to the herbicide group number printed on the label, the way herbicides enter and move within plants, and the characteristic injury each group produces. Special emphasis is placed on recognizing herbicide injury, matching the mode of action to the site, and rotating groups to prevent herbicide resistance. Go ahead and get started!

Learning Objectives:

The following is a list of the key points to be discussed within this course.

• Explain the difference between mode of action and site of action, and identify the herbicide group number on a pesticide label.
• Describe how herbicides are absorbed through leaves and roots and how they move in the xylem and phloem.
• Explain how growth regulators, glyphosate, ALS inhibitors, photosynthesis inhibitors, PS I inhibitors, PPO inhibitors, seedling growth inhibitors, lipid synthesis inhibitors, and pigment inhibitors kill plants.
• Identify the characteristic injury symptoms produced by each herbicide group and apply a systematic approach to diagnosing herbicide injury.
• Describe how to select and rotate modes of action for aquatic sites, natural areas, row crops, and tree crops to prevent resistance.

Florida Course Approval

Tyler Pettis – Director of Training