Iowa State University


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Spray additives for postemergence herbicides
by Brent Pringnitz and Bob Hartzler

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The following is a Powerpoint slide presentation developed for the 1997 Private Pesticide Applicator Training program.   To begin the show, click here or select the slide you wish to view from the list below.

Objectives: This presentation is designed to provide the producer with background information on herbicide additives, their function, and selection. There are many additives available to choose from, and making the correct selection can be difficult. By understanding how the individual components function, better choices can be made. The last portion of the presentation deals with crop injury issues as they relate to additives.

Table of Contents

Spray Additives for Postemergence Herbicides

Reasons for Increase in Postemergence Herbicides

Steps for Consistent Postemergence Weed Control

Different Roles of Spray Additives

Herbicide Absorption

Types of Spray Additives

Reduction in Droplet Surface Tension

Types of Surfactants

Crop Oil Concentrates

Nitrogen Fertilizers

Selecting Additives for Postemergence Use

Selection Criteria

Additive Selection Influences Both Weed Control and Crop Safety

Additive Selection for Herbicide Tank-Mixes

Selecting Additives


Prepared by Brent Pringnitz, extension program specialist, Department of Agronomy, Iowa State University

For more information contact:
ISU Extension Agronomy
2104 Agronomy Hall
Ames, Iowa 50011-1010
Voice: (515) 294-1923
Fax: (515) 294-9985
This site designed and managed by Brent Pringnitz.
Submit questions or comments here.  

Copyright 1996-2003, Iowa State University, all rights reserved  

Common chemical and trade names are used in this publication. The use of trade names is for clarity by the reader. Inclusion of a trade name does not imply endorsement of that particular brand of herbicide and exclusion does not imply nonapproval.