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Weeds Publications & Resources

2021 PNW Weed Management Handbook > HTML
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 we . . . . . more details

Alaska Field Guide to Potato Pests and Beneficial Insects in English and Russian > PDF
This 128-page pocket-sized manual helps potato field workers scout for and identify economically important diseases, insects, and weeds in potato crops in Alaska. Each pest or beneficial insect is ass . . . . . more details

Black Medic > HTML
Black medic (Medicago lupulina) is an annual or short-lived perennial from Eurasia. It can be found in lawns, pastures, rights-of-way, and other marginal sites. Learn how to manage this summe . . . . . more details

Broadleaf Plantain (Plantago major L.) > HTML
Broadleaf plaintain is a hardy perennial weed that thrives in lawns, fields, and roadsides and in other areas prone to trampling. Along with a profile description, this Idaho Green Thumb How-To’s publ . . . . . more details

Bull Thistle: Identification and Control > Video
Bull thistle is a biennial, which means it typically takes two growing seasons to complete its life cycle. This video will introduce you to the life cycle of Bull thistle, how to identify it, concerns . . . . . more details

Curlycup Gumweed > HTML
Curlycup gumweed (Grindelia squarrosa) (Pursh) Dunal is native to North America except in the southeastern United States. This forb (herbaceous broadleaf plant) is commonly found along roadsi . . . . . more details

Different Treatment Options for Russian Olive > HTML
Russian olive is a thorny, small, and highly invasive tree that thrives in southern Idaho’s arid climate. The sometimes shrubby tree often crowds out native vegetation areas along the banks of waterco . . . . . more details

Eurasian Watermilfoil > PDF
Covers the biology, detection, and management of this invasive aquatic plant. Includes illustrations and descriptions of similar species and estimated costs for various control options, including trea . . . . . more details

Field Guide for Integrated Pest Management in Pacific Northwest Vineyards
To produce high-quality wine and juice grapes, effective pest management is essential. The second edition of Field Guide for Integrated Pest Management in Pacific Northwest Vineyards addresse . . . . . more details

Flowering Rush > HTML
Flowering Rush is an invasive, aquatic, perennial weed listed as a "noxious" weed by the Idaho State Department of Agriculture (ISDA). This fact sheet provides basic information on identification, hab . . . . . more details

From Weeds to Flowers: Creating Sustainable Wildflower Meadows in Arid Climates > HTML
Wildflower meadows have the potential to benefit homeowners, public land managers, and commercial property caretakers in numerous ways. They can beautify landscapes, simplify maintenance, strengthen s . . . . . more details

Harvest Weed Seed Control: Applications for PNW Wheat Production Systems > PDF
This publication discusses the various HWSC systems and their potential suitability for PNW wheat production systems across rainfall regions. Authors: Drew J. Lyon, Michael J. Walsh, Judit . . . . . more details

Herbicide-Resistant Weeds and Their Management > PDF
Keep weeds in your fields from becoming herbicide resistant by rotating among herbicides regularly. Learn how and why in this publication. Especially useful is a color-coded chart to help you distin . . . . . more details
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Idaho's Noxious Weeds, 9th edition > PDF

This newest edition of our popular pocket guide shows all the weeds on Idaho's official noxious weeds list, including examples of brooms—all of which are now prohibited in . . . . . more details


Improving Weed Control in Dry Bean Using Narrow Planting > HTML
Season-long control of weeds is an important goal when growing dry beans. Hairy nightshade, lambsquarters, redroot pigweed, and green foxtail in particular harm bean yields in southern Idaho. This bul . . . . . more details

Integrated Management of Downy Brome in Winter Wheat > PDF
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 . . . . . more details

Integrated Management of Feral Rye in Winter Wheat > PDF
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 so . . . . . more details

Integrated Management of Jointed Goatgrass in the Pacific Northwest > PDF
Describes the components of an integrated system to manage jointed goatgrass, a particular problem in direct seed/reduced tillage management systems. The bulletin covers prevention, mechanical control . . . . . more details

Integrated Management of Mayweed Chamomile in Wheat and Pulse Crop Production Systems > PDF
In small grain and pulse crops throughout the high rainfall zones of the Inland Pacific Northwest, mayweed chamomile is a troublesome weed. Individual plants can produce as many as 17,000 seeds, and s . . . . . more details

Integrated Management of Mustard Species in Wheat Production Systems > PDF
Blue mustard, flixweed, and tumble mustard can be a headache to control when it comes to winter wheat; this article shows you how it can be done. Authors: Drew Lyon, Ian Burke, Joan Campbel . . . . . more details

Integrated Management of Prickly Lettuce in Wheat Production Systems > PDF
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 resist . . . . . more details

Integrated Management of Wild Oat in the Pacific Northwest > HTML
In the Pacific Northwest (PNW), wild oat has become a notable weed pest of small grain and rotational crops, including pulse crops, potato, sugar beet, and oilseed crops. It has infested more than 3 m . . . . . more details

Integrated Weed Management in Dry Edible Beans > PDF
Describes problem weed species and the steps-prevention, cultural control, mechanical control, and chemical control-involved in integrated weed management. Includes 20 full-color photographs of weed . . . . . more details

Jointed Goatgrass Best Management Practices: Intermountain Region > PDF
Learn methods for preventing and controlling jointed goatgrass, a weed of particular concern in the intermountain region where low moisture increases the weed's competitiveness with wheat. . . . . . more details

Knotweed Shrubs: Identification, Biology, and Management > PDF
Being able to correctly identify the five knotweeds that grow in the Northwest can help you choose the best control strategies. Color photographs of the weeds accompany a detailed chart describing t . . . . . more details

Know Your Herbicide-Resistant Weeds > PDF

The number of herbicide-resistant weeds continues to increase in the United States. This is a huge concern for farmers, since weeds compete with crops for nutrients in the so . . . . . more details


Management of Goats for Controlling Noxious Weeds: A Primer > PDF
This publication presents an introduction to the use of goats for controlling noxious weeds, including the use of different goat management methods for various weed conditions. Authors: Sha . . . . . more details

Management Strategies for Preventing Herbicide-Resistant Grass Weeds in Clearfield Wheat Systems > PDF
Based on computer modeling, the publication describes herbicide rotation strategies aimed at preventing the buildup of herbicide-resistant grass weeds (downy brome, jointed goatgrass, and wild oat) . . . . . more details

Matrix in Weed Management Systems for Potatoes > PDF
Provides information on Matrix's mode of action, its effectiveness on various weed species, and how to use it to maximize its strengths and avoid hazards of misuse. Authors: Pamela Hutchi . . . . . more details

Meadow Deathcamas in the Pacific Northwest > PDF
Found in all areas of the Pacific Northwest, meadow deathcamas (Toxicoscordion venenosum) is capable of killing livestock whether eaten as forage or in dried hay. Human poisonings have been reported i . . . . . more details

Mustards in Mustards: Guide to Identification of Canola, Rapeseed, and Related Weeds > PDF
This four-color, field-oriented identification guide allows users to identify rapeseed, canola, and mustard crop plants and their related weeds. A durable folder holds nine full-color identification c . . . . . more details
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Nightshade: Biology and Control in the Pacific Northwest > PDF
Covers nightshade distribution in the Pacific Northwest; identification of hairy, black, cultleaf, and bittersweet nightshades; nightshade biology and toxicity; crop damage; and control practices for . . . . . more details

Outlook Herbicide for Weed Control in Potatoes > PDF
Describes mode of action, use rates, application methods, weeds controlled, potato variety tolerances, and follow-crop restrictions. Provides UI research data on percentage control of various weeds in . . . . . more details

Oxeye Daisy > PDF
How to recognize and manage oxeye daisy in pastures, rangelands, and road sides. Color photographs.
Authors: Steven Hines, Timothy S. Prather and Sandra Robins 4 pages . . . . . more details


Oxeye Daisy Bandana – Red
100% cotton red bandana with white print -- 21"x 21". Designed by Apparel, Textiles & Design students in collaboration with Valley County Extension. White daisies, leaves, and antlers on bold red back . . . . . more details
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Oxeye Daisy Scarf
100% polyester twill scarf with rolled hem -- 36”x 36”. Designed by Apparel, Textiles & Design students in collaboration with UI Extension Valley County. White daisies, green stems & leaves, brown ant . . . . . more details
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Pacific Poison-oak and Western Poison-ivy: Identification and Management > PDF
Pacific poison-oak and western poison-ivy are both native to the Pacific Northwest. All parts of these plants contain urushiol, an oily toxin that can cause an allergic reaction of contact dermatitis. . . . . . more details

Pasture and Range Plants that Endanger Livestock in Southwestern Idaho > PDF

This publication is a basic guide to thirty-five common toxic plants found in southwestern Idaho pastures and rangelands. Concise plant descriptions, paired with stunning pho . . . . . more details


Pasture Principles for Smaller Acreages > HTML
Ranchettes and small farms are cropping up in rural landscapes across Idaho, spurring demand for information on pasture management. This updated publication addresses the most common concerns (scripti . . . . . more details

Paterson's Curse (Echium plantagineum) in the Pacific Northwest > PDF
Describes the weed, its habitat and dispersal mechanisms, and management strategies to prevent its introduction and to control it through manual removal, herbicide use, and biological control agents.< . . . . . more details

Pigweeds: Current and Emerging Weed Threats in the Pacific Northwest > HTML
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 pre . . . . . more details

Puncturevine > PDF
With a spiny fruit capable of injuring hooves, feet, and vehicle tires, growers from across the spectrum can learn to effectively manage this weed. Authors: Dale K. Whaley, Robert Parker, R . . . . . more details

Quick Facts — Idaho Beans > HTML
This two-page fact sheet offers recommendations for growing dry beans in southern Idaho, with pointers on soil sampling and testing, fertilization, irrigation, and insect, weed and disease control. It . . . . . more details

Rattail Fescue: Biology and Management in Pacific Northwest Wheat Cropping Systems > PDF
Mitigating rattail fescue has become easier: this publication addresses this increasingly common weed in Pacific Northwest cropping systems. Authors: Drew J. Lyon, Daniel A. Ball, and Andre . . . . . more details

Rush Skeletonweed > PDF
Rush skeletonweed is an exotic herbaceous biennial or creeping perennial plant that aggressively infests rangeland, cropland, and disturbed areas. Along with explanations of management strategies, thi . . . . . more details

Russian Olive Trees: Control and Management in the Pacific Northwest > HTML
Russian olive trees are fast-growing plants that since the 1950s have become invasive throughout many areas of the Inland Pacific Northwest, particularly in riparian ecosystems. They form impenetrable . . . . . more details

Russian Thistle: Management in a Wheat-Fallow Crop Rotation > PDF
Russian thistle is the most economically important summer-annual broadleaf weed found in the low-precipitation zone of the inland Pacific Northwest. This weed causes serious management problems in whe . . . . . more details

Scotch Broom > HTML
Introduced in California in the 1850s, Scotch broom is an ornamental whose golden blooms hide a dangerously prolific invasive plant. Its ability to outcompete other plants has incurred significant man . . . . . more details

Scotch Thistle > PDF
Scotch thistle is a noxious regional weed that was introduced to the United States in the 1800s as an ornamental plant from the Mediterranean region. At its worst, it forms dense, virtually impenetrab . . . . . more details

Spotted Knapweed Bandana - Gold
100% cotton gold bandana with white print -- 21”x 21”. Designed by Apparel, Textiles & Design students in collaboration with UI Valley County Extension. The design incorporates the specific identifyin . . . . . more details
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Spotted Knapweed Bandana - White
100% cotton white bandana with white print -- 21”x 21”. Designed by Apparel, Textiles & Design students in collaboration with UI Valley County Extension. The design incorporates the specific identifyi . . . . . more details
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Spotted Knapweed Scarf
100% polyester twill scarf with rolled hem -- 36”x 36”. Designed by Apparel, Textiles and Design students in collaboration with UI Extension Valley County. The design incorporates the specific identif . . . . . more details
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Spotted Spurge (Chamaesyce maculata; Synonym: Euphorbia maculata) > HTML
Spotted spurge is a summer weed that grows close to the ground in sidewalk cracks, roadsides, gardens, or drought-stressed lawns. Its presence can be helpful, because it often indicates an underlying . . . . . more details

Strategies to Minimize the Risk of Herbicide-Resistant Jointed Goatgrass > PDF
Jointed goatgrass is a winter annual grass weed whose genetics are similar to winter wheat. Thus its control is challenging—it can hybridize with wheat and possibly develop resistance to herbicides. T . . . . . more details

Targeted Tank Mixtures for Weed Control in Potatoes > HTML
Managing weeds in potato fields with an integrated approach—using all available cultural, mechanical, chemical, and biological tools—is more effective than relying on any single weed-contr . . . . . more details

Threat-Based Land Management in the Northern Great Basin: A Field Guide > PDF
Sagebrush ecosystems in the northern Great Basin are threatened by encroaching juniper and invasive annual grasses. This guide presents a simplified framework to help land managers assess and monitor . . . . . more details
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Threat-Based Land Management in the Northern Great Basin: A Manager’s Guide > HTML
Sagebrush ecosystems in the northern Great Basin are threatened by encroaching juniper and invasive annual grasses. This guide presents a simplified framework to help land managers assess and monitor . . . . . more details
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Weed and Vegetation Management in Christmas Trees > PDF
Describes the top dozen weeds in Christmas trees and strategies for managing them, including prevention, mechanical control, control with cover crops and vegetated strips, flame weeding, biological co . . . . . more details
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Weed Control in Idaho Lawns > HTML
Weeds are opportunistic and readily invade stressed or unhealthy lawns. Many weeds found in Idaho lawns can be prevented and controlled by following some basic management principles, including underst . . . . . more details

Weed Control Methods for Perennial Crops > PDF
Weed control for perennial crops requires more than yearly tillage and crop rotation. Indeed, practices like repeated cultivation, herbicide application, or their combination prove the best additions. . . . . . more details

Western Waterhemlock in the Pacific Northwest > PDF
Western waterhemlock (xCicuta douglasii) is the most poisonous plant in North America—a piece of root no larger than a walnut can kill a mature cow. Every part of the plant is toxic. To help . . . . . more details

White Bryony > HTML
A poisonous noxious weed, white bryony grows rapidly and can smother and kill small trees and shrubs. Learn its characteristics and how to identify and control it in this profile of the viny member of . . . . . more details

White Campion or White Cockle > PDF
White campion or white cockle infests hay fields, roadsides, ditches, and fencerows. Learn how to identify, prevent, and control white this prolific seed producer in this three-page profile, lushly il . . . . . more details

Wild Carrot > PDF
An abundant seed producer, wild carrot grows in meadows, pastures, along roadsides, and in noncrop areas. A Class B noxious weed in Washington, the pest ruins cultivated carrot seed and possibly is mi . . . . . more details

Yellow Toadflax Bandana - Navy
100% cotton navy bandana with white print -- 21” x 21”. Designed by UI Apparel, Textiles & Design students in collaboration with UI Valley County Extension. Individual sketches of flower heads, leaves . . . . . more details
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Local Information

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University of Idaho Extension


Physical Address:
E. J. Iddings Agricultural Science Laboratory, Room 10
606 S Rayburn St

Mailing Address:
875 Perimeter Drive MS 2332
Moscow, ID 83844-2332

Phone: 208-885-7982

Fax: 208-885-9046



Barbara Petty