Weeds

Weeds are considered the #1 pest in agroecosystems. They compete with desirable plants and can reduce yields, and alter soil structure and quality. Weed management requires thoughtful planning and action. Use the resources below to help reduce the effect of weeds in your crop, garden, or landscape.

PNW Weed Management Handbook

By Ed Peachey

This comprehensive guide to weed management in the Pacific Northwest covers biological weed control agents; pesticide safety and disposal; agrichemicals and their properties; and control of problem weeds.

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Photo Credit: Jonne Huotari - Unsplash.com (Cropped from original)

Featured Resources

Malheur Experiment Station virtual field tour - Controlling Glyphosate resistant weeds in sugarbeets

Learn about an applied research project that is testing herbicides for the control of glyphosate resistant weeds in sugarbeets.

Christy Tanner, Joel Felix | Nov 2024 | Video Peer reviewed (Gray level)

Malheur Experiment Station Virtual Field Tour - Sonalan Tank Mixes for Weed Control in Potato

Learn about an applied research project evaluating tank mixes of the herbicide Sonalan for controlling weeds in potato.

Christy Tanner, Joel Felix | Aug 2020 | Video Peer reviewed (Gray level)

Onion Response to Talinor Herbicide - A Virtual Field Tour

A Malheur Experiment Station virtual field tour. Weed Scientist Joel Felix discusses a field trial evaluating the herbicide Talinor for use in onions.

Christy Tanner | Aug 2020 | Video Peer reviewed (Gray level)

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Having weed problems?

Solve Pest Problems is a partnership between OSU and Oregon stakeholders to provide a user-friendly online resource to help urban and rural property managers to solve pest problems. Learn research-based, safe, and effective tactics for common garden and property pests and weeds. We provide non-chemical methods alongside the most effective and least toxic chemical options available, to reduce risk to people and the environment.

Learn more

Common weeds

Pigweeds: Current and Emerging Weed Threats in the Pacific Northwest

Pigweed is an invasive plant pest usually found in disturbed areas, like farmland and along roadsides and fencelines. Because their aggressiveness can reduce crop yields, this PNW discusses how to prevent or curtail...

Albert Adjesiwor, Timothy S. Prather, Joel Felix | Jun 2023 | Extension Catalog publication Peer reviewed (Orange level)

Integrated Management of Prickly Lettuce in Wheat Production Systems

Prickly lettuce is a common weed in wheat production systems throughout the PNW, but it’s difficult to manage. Herbicides can control prickly lettuce in wheat, but many biotypes have developed resistance. An ...

Drew J. Lyon, Ian C. Burke | Feb 2021 | Extension Catalog publication Peer reviewed (Orange level)

Integrated Management of Downy Brome in Winter Wheat

Downy brome (Bromus tectorum L.), also known as cheatgrass, is especially troublesome in low precipitation production areas where crop rotations are mostly limited to winter wheat followed by a year of summer ...

Drew J. Lyon, Andy Hulting, Don W. Morishita, Frank Young | Jun 2023 | Extension Catalog publication Peer reviewed (Orange level)

Integrated Management of Feral Rye in Winter Wheat

Feral rye (Secale cereale L.), also known as volunteer rye, is a troublesome weed in winter wheat production in the low- and intermediate-rainfall zones of eastern Washington and Oregon and southern Idaho. This ...

Drew J. Lyon, Andy Hulting, Judit Barroso, Joan Campbell | Jun 2020 | Extension Catalog publication Peer reviewed (Orange level)

Puncturevine

A member of the Caltrop family, this weed produces woody fruits that always land with one sharp spine pointed upward. Spines injure hooves, feet, and vehicle tires. A toxin from the plant may be linked to ...

Robert (Bob) Parker, Rick Boydston, PhD | Apr 2020 | Extension Catalog publication Peer reviewed (Orange level)

More common weed guides

Best Management Practices for Managing Herbicide Resistance

By Drew J. Lyon, Judit Barroso, Joan Campbell, Doug Finkelnburg and Ian C. Burke

Learn to manage herbicide-resistant weeds on your farm using the most effective methods, also known as best management practices (BMPs).

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Photo Credit: Marcel Poncu - Adobe Stock (Cropped from original)

Latest Resources

Weed Competition and the Critical Weed Free Period in Hemp (Cannabis sativa L.)

The high summertime temperatures experienced in southern Oregon can result in prolific weed growth in hemp production systems. Growers close to the coast region can experience even more weed pressure due to substantial rainfall. ...

Matthew Cutulle, Govinda Shrestha | Aug 2024 | Article Peer reviewed (Gray level)

What is this weed that has overtaken my pasture?

Q: This weed has overtaken my horse pasture in large amounts this year. I’m trying to identify it and I’ve come up with two possibilities but I’m not sure which one it is. Possibly hedge mustard or creeping yellowcress? ...

A: View answer | View all featured questions

Managing Hypochaeris Radicata may prevent Stringhalt Disease in horses

A debilitating condition in horses called stringhalt may be associated with Hypochaeris radicata, also known as false dandelion, flatweed, common catsear or summer dandelion. This invasive species is common in pastures throughout Oregon.

Melissa Fery | Jun 2024 | Article Peer reviewed (Gray level)

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Latest News

Living on the Land supports small-acreage landowners in the south Willamette Valley

OSU Extension collaborates with Oregon’s Soil and Water Conservation Districts and watershed councils to develop the series to best address natural resources concerns in the local area.

Melissa Fery | Apr 2024 | Impact story

Extension equips Baker County land managers to face the challenge of invasive and noxious weeds

A post-workshop evaluation found that 100% of respondents indicated that they planned to incorporate at least one item from the workshop into their management actions.

Will Price | Mar 2024 | Impact story

How to manage three common weeds in the vegetable garden

Vegetable gardeners most commonly deal with annual weeds, which spread only by seed and die when the weather turns cold.

Jul 26, 2023 | News story

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Meet Our Experts

Judit Barroso

Weed Science

Marcelo Moretti

Assistant Professor

Contact me with questions about weed management in commercial agriculture.

Cassie Bouska

Agriculture

Contact with me with questions about agriculture in Coos and Curry counties

Brooke Edmunds

Community Horticulture, Master Gardeners

Contact me about the Master Gardener Program or gardening questions from Marion or Polk counties

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What is this weed that has overtaken my pasture?

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