Weed Science Extension

Weed management resources

Our slideshows and videos address an array of weed management issues, such as herbicide resistance, pasture weed management, and off-target herbicide movement.

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What weeds are these?

Our Weed ID Guide will help you identify weeds in your crops, gardens, lawns, pastures and even ponds.

Identify your weeds

The Weed Science program at the University of Missouri administers extension, research and teaching programs to keep you informed of the latest findings in weed management.

Our online resources include a Missouri weed ID guide and a herbicide injury guide. Both of these guides are full of photos — to aid in the identification of a weed or the diagnosis of herbicide-caused crop injury, respectively. They are also available as mobile apps. In addition, we offer numerous publications, newsletter articles, videos and PowerPoint presentations on various aspects of weed control.

ID Weeds and Herbicide Injury ID app icons

ID weeds or herbicide injury on-the-go with one of our apps

News & articlestab

News & articles

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Cereal rye as a cover crop can reduce waterhemp

Published: Wednesday, July 28, 2021

COLUMBIA, Mo. – Cereal rye as a cover crop may reduce waterhemp populations without yield loss in soybean, according to a three-year study at the University of Missouri.MU Extension weed specialist Mandy Bish and a team of researchers studied how ...

Weed electrocution research sparks interest as herbicide resistance impedes current methods

Published: Thursday, July 22, 2021

COLUMBIA, Mo. – Move over, herbicides. There’s a new sheriff in town. And he’s toting some powerful guns loaded with electricity to kill weeds. This shocking new method of weed control was demonstrated at the 2021 Pest Management Field Day at ...

Mizzou Weed Science shares Seed Terminator research

Published: Monday, July 19, 2021

COLUMBIA, Mo. – In the 1984 film “The Terminator,” a robotic assassin played by Arnold Schwarzenegger warns, “I’ll be back.” If waterhemp could talk, it might say the same thing. Waterhemp can’t be bargained with. It can’t be ...

MU research looks at technology to kill weeds

Published: Friday, Dec. 18, 2020

COLUMBIA, Mo. – If it’s a weed, spray it. That’s the mindset that most in the agriculture industry held for years.That thinking no longer works as more weeds become resistant to herbicides, says Kevin Bradley, University of Missouri Extension ...

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Publications

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Missouri Weed Seeds

Publication date: Nov. 1, 2018

Positive identification of pests, including weeds, is the first step in a sound integrated pest management program. Knowledge of plant morphological features, such as leaf and stem shape, flower type and color, and the presence of hairs make ...

Weed Identification and Herbicide Injury Guide for Corn and Soybean

Publication date: Nov. 1, 2018

$30.00

Check out our ID Weeds app to help identify weeds,Apple App for iPhones, iPads.Google Play Store for Android devices.Mandy BishDivision of Plant SciencesIn corn and soybean cropping systems throughout the Midwest, weeds represent an economically ...

Kochia Management in Soybeans

Publication date: March 1, 2018

Kochia is well adapted to the Great Plains and western regions of the U.S. and Canada. It can emerge as early as February in Kansas and March in the northern Great Plains, but germination can extend through August throughout the Great Plains states. ...

Velvetleaf Management in Soybeans

Publication date: March 1, 2018

Velvetleaf — also known as elephant ear, buttonweed and butterprint — is a common weed species found in most fields throughout the soybean belt. It can be extremely competitive with soybeans and reduce yields by 25 to 40 percent. This fact sheet ...

Palmer Amaranth Management in Soybean

Publication date: Jan. 1, 2018

Native to the southwestern United States, Palmer amaranth (aka Palmer pigweed) has become a devastating weed problem in the South and has recently spread to the Upper Midwest. This fact sheet provides guidance on how to manage this difficult weed in ...

Herbicide-Resistant Horseweed (Marestail) Management in No-Till Soybean

Publication date: Jan. 1, 2018

Horseweed (marestail), which has two primary periods of emergence, competes with soybeans throughout the growing season and reduces crop yield. This fact sheet lists steps for managing horseweed in your soybean fields.

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2015 Field Day: Control of Marestail/Horseweed (video)

MU Extension State Specialist Kevin Bradley presents burndown programs for difficult to control marestail, or horseweed, at the 2015 Mizzou Pest Management Field Day.

ID Weeds app (Google Play)

ID Weeds allows you to search for weeds by their common or Latin name, view a list of weeds, or identify weeds based on characteristics. It presents weed details and photos. By the MU Division of Plant Sciences, this is the Android version.

Sensitivity of Various Tree and Ornamental Species to 2,4-D and Dicamba (PDF)

Waterhemp Management in Soybean (PDF)

Waterhemp can reduce soybean yield by 44% if left to compete over the season. Control in soybean is challenging because the species rapidly adapts to herbicides and develops resistance. Best control options will use cultural techniques with ...

2014 Field Day: Comparing Palmer Amaranth to Common Waterhemp (video)

MU Extension State Specialist Kevin Bradley shares characteristics that can help distinguish between waterhemp and Palmer amaranth at the 2014 Mizzou Pest Management Field Day.

2013 Field Day: Horseweed Stop (video)

MU Extension State Specialist Kevin Bradley discusses the importance of controlling marestail, or horseweed, prior to soybean planting at the 2013 Mizzou Pest Management Field Day.

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Weed ID Guide
- Identify weeds you encounter in your crops, gardens, lawns, pastures and even ponds.
What the research says
- Search for the latest MU field research results by year, herbicide, weed or crop.
Slideshows and videos
- View videos and PDFs of slideshows about weed management.

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Weed Science Extension

Weed management resources

What weeds are these?

Weed science fun facts

An average waterhemp plant typically produces around 300,000 seeds that are the size of a pin head.

Weed science fun facts

Scientists have discovered that earthworms contribute to the spread of giant ragweed by systematically collecting and burying its seeds in their burrows.

Weed science fun facts

After a walk, Swiss engineer George de Mestral observed burs from common burdock (Arctium minus) stuck to his wool pants and his dog’s fur. A few years later he patented Velcro, an invention inspired by the weed.

Weed science fun facts

Each acre of U.S. cropland contains 50 to 300 million buried weed seeds. Five to 10 percent of them germinate and emerge each year.

Weed science fun facts

Common ragweed plants typically release a billion pollen grains per plant from August through October, triggering allergic reactions for nearly 36 million Americans annually.

Weed science fun facts

Herbicides make it possible for American growers to use no-till production on 52 million acres, preventing 304 billion pounds of soil erosion annually.

Weed science fun facts

Ancient Egyptians wrapped their dead in the leaves of the giant reed (Arundo donax), now one of the worst riparian weeds in the U.S.

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News & articles

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Publications

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Weed ID Guide

What the research says

Slideshows and videos

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Weed Science Extension

Weed management resources

What weeds are these?

Weed science fun facts

An average waterhemp plant typically produces around 300,000 seeds that are the size of a pin head.

Weed science fun facts

Scientists have discovered that earthworms contribute to the spread of giant ragweed by systematically collecting and burying its seeds in their burrows.

Weed science fun facts

After a walk, Swiss engineer George de Mestral observed burs from common burdock (Arctium minus) stuck to his wool pants and his dog’s fur. A few years later he patented Velcro, an invention inspired by the weed.

Weed science fun facts

Each acre of U.S. cropland contains 50 to 300 million buried weed seeds. Five to 10 percent of them germinate and emerge each year.

Weed science fun facts

Common ragweed plants typically release a billion pollen grains per plant from August through October, triggering allergic reactions for nearly 36 million Americans annually.

Weed science fun facts

Herbicides make it possible for American growers to use no-till production on 52 million acres, preventing 304 billion pounds of soil erosion annually.

Weed science fun facts

Ancient Egyptians wrapped their dead in the leaves of the giant reed (Arundo donax), now one of the worst riparian weeds in the U.S.

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Weed ID Guide

What the research says

Slideshows and videos

Meet the experts