IWM Toolbox

Integrated weed management (IWM) means integrating multiple weed control tactics into a weed management program, to optimize control of the particular weed problem. The past several decades have seen simplified weed control practices that rely heavily on a few popular herbicides. However, the rapid spread of herbicide resistant weeds has pushed producers and agronomists to explore additional options in order to maintain weed control. Increased consumer demand for organic and sustainable agriculture has also motivated a push toward alternative weed management.

Weed Management Tactics Form a Toolbox of IWM

IWM can be thought of as a “toolbox” of weed management strategies, or “tools.” The set of “tools” a producer chooses to tackle a particular weed problem should be based on what’s best for the specific situation. The “toolbox” includes chemical (herbicide), mechanical, cultural, biological practices, and weed prevention measures.

IWM tactics span a wide range of types and complexity. Many IWM tactics can be integrated without substantial change to current management programs, while others require more intensive planning and implementation. Some examples include: Equipment cleaning, timely scouting, altering herbicide tank mixes, rotating herbicides, cover cropping, changing tillage practices, and hand-pulling weeds.

IWM is not an alternative to herbicides in conventional crops

For many decades, herbicides have been the primary means of weed management in conventional crops due to their simplicity, effectiveness, and affordability. IWM is about using all options available to best solve the problem – in many cases in conventional crops, herbicides are part of this solution.

Why now?

For some producers who are strongly effected by herbicide resistance, IWM is necessary to maintain weed control. The main driver for altering weed control practices is when current strategies are no longer effective, or a new weed enters a field and requires a change in plan. In addition, the recent increase in consumer demand for organic products has also motivated some producers to integrated new weed management practices in the absense of herbicides.

What resources are available for learning about & implementing IWM strategies?

Numerous resources from around the US are available here on this site – find these under Cultural, Mechanical, Chemical, Biological, Prevention, and Harvest Weed Seed Control. At the state level, state university extension weed scientists offer in-person and online training that is catered to their particular state or region.

For up-to-date recommendations for specific weeds, explore the Weed Info tab on the homepage.

Introductory resources about IWM:

“Still Don’t Think You Need Integrated Weed Management?” – Iowa State University

A summary of IWM strategies – Penn State University

Integrated Weed Management: What It Is, Why It’s Important – Ohio Soybean Council

University of Illinois Agronomy Guide – Weed Management – University of Illinois

Field Crop Weed Management for Illinois – University of Illinois

Integrated Weed Management as described by Australian weed scientists at the forefront of IWM development

Successful Weed Management Must Respect the Rotation – University of Delaware

Archive of Weed Management Recommendations and News – Iowa State University

Weed Management in Texas Cotton – Texas A&M University

VIDEO: Using multiple effective herbicide modes of action