Publications and Videos

Winter Annual Grasses

Integrated Management of Wild Oat in the Pacific Northwest
Abstract: 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.

Integrated Management of Downy Brome in Winter Wheat
Abstract: Downy brome (Bromus tectorum L.), also known as cheatgrass, was introduced into North America from the Mediterranean area of Europe. Downy brome is a major weed problem in winter wheat.

Common Weeds List

Weed Control Reports

Herbicide Resistance Resources

Tools & Calculators

Integrated Management of Feral Rye in Winter Wheat (PNW660)
Abstract: Feral rye (Secale cereale L.), also known as volunteer or cereal rye, is a troublesome weed in winter wheat production systems in the low and intermediate rainfall zones of eastern Washington and Oregon, and southern Idaho.

Integrated Management of Jointed Goatgrass in the Pacific Northwest (EB2042E)
Abstract: Jointed goatgrass (Aegilops cylindrica) is an annual invasive grass weed that is particularly troublesome in winter wheat fields in the western United States. The severity of the infestation has increased over the past 50 years in many areas to levels that reduce yield and quality significantly.

Jointed Goatgrass Ecology (EB1932)
Abstract: Jointed goatgrass management in winter wheat has been difficult because the genetics and growth patterns of these two species are similar. Knowledge of jointed goatgrass growth characteristics can help producers select effective management strategies, as some attributes of jointed goatgrass respond to control practices.

Jointed Goatgrass Genetics (EB1934)
Abstract: The common genetic background of wheat and jointed goatgrass makes jointed goatgrass control in winter wheat difficult and increases the chance of successful gene flow, including resistance genes transferring from herbicide-resistant wheat to jointed goatgrass.

Rattail Fescue: Biology and Management in Pacific Northwest Wheat Cropping Systems (PNW613)
Abstract: Farmers are discovering that weed management practices must be adjusted to control species previously susceptible to tillage as direct-seed wheat production practices become more widely adopted to conserve soil and water resources. Rattail fescue (Vulpia myuros) is an example, as this grass is becoming an increasingly common weed in wheat-based cropping systems across the Pacific Northwest. Rattail fescue has been a management problem in southern Australian pastures and wheat-based cropping systems since the mid-1980s, and more recently it has become particularly widespread in PNW wheat-cropping systems as minimum-tillage and direct-seeding practices have become commonplace throughout the region.

Videos

Integrated Weed Management (IWM) with Dr. Ian Burke

Biology and Management of Smooth Scouringrush in Wheat

Italian Ryegrass and Downy Brome in Winter Wheat in Dixie, WA

Annual Grasses

Broadleaf Weeds

Buckwheat Control in Wheat (FS158E)
Abstract: Washington State is a large producer of buckwheat (Fagopyrum esculentum), much of which is exported overseas. Buckwheat is a popular crop choice for some Washington farmers with irrigated land because it’s a second crop they can plant in midsummer after wheat, timothy hay, or pea harvest. Washington also exports much of its wheat crop overseas.

Control of Common Barberry to Reduce Stem Rust of Wheat and Barley (FS151E)
Abstract: The common barberry (Berberis vulgaris) is a woody shrub that is the alternate host for the stem rust pathogen of wheat and barley.

Field Bindweed (PNW580) (pdf)
Abstract: Field bindweed (Convolvulus arvensis L.: Convolvulaceae) is one of the most common noxious weeds in the Pacific Northwest (PNW) and one of the most difficult to control.

Integrated Management of Mayweed Chamomile in Wheat & Pulse Crop Production Systems (PNW695)
Abstract: Mayweed chamomile (Anthemis cotula) is a troublesome weed in small grain and pulse crops throughout the high rainfall zones of the Inland Pacific Northwest (PNW). It is an annual that can germinate in the fall or spring and that reproduces only by seed. Individual plants can produce as many as 17,000 seeds, and seed remain viable in the soil for many years. Preventing seed production is the key to managing mayweed chamomile! While herbicides are an effective tool for mayweed chamomile control, herbicide-resistant biotypes are an increasing concern. An integrated management approach is required for the sustainable, long-term control of this species.

Integrated Management of Mustard Species in Wheat Production Systems (PNW703)
Abstract: Mustard species commonly infest winter wheat fields and can cause significant yield losses if not controlled. This publication focuses on blue mustard (Chorispora tenella), flixweed (Descurainia sophia), and tumble mustard (Sisymbrium altissimum), although many of the management recommendations apply to other mustard species as well. Prevention can play an important role in managing mustard species since infestations often begin along field edges. There are a number of herbicides that can provide effective control of mustard species, but these must be applied early before the plants get large or enter the reproductive stage when rapid stem elongation begins. Mustards should be controlled by late winter or early spring!

Integrated Management of Prickly Lettuce in Wheat Production Systems (PNW688)
Abstract: 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 integrated management approach is required for sustainable, long-term control of this troublesome species. This publication outlines both how to identify prickly lettuce and how to manage it in wheat.

Managing Russian Thistle (PNW492)
Abstract: Reviews Russian thistle biology as it relates to management, including seed dormancy and longevity in soil, seed distribution, seed germination and emergence, plant growth after establishment, crop competition, and resistance to herbicides. Outlines key considerations for managing for 3 crop years and 1 fallow year. Describes results from a residue management experiment designed to determine how to reduce tillage while maintaining winter wheat production.

Rush Skeletonweed (PNW465)
Abstract: Rush skeletonweed is an aggressive plant that infests cropland, rangeland, and other disturbed areas.

General

Herbicide Rainfast Times (pdf)
Abstract: The rainfast periods for herbicides labeled for use in Washington wheat production are provided in this publication.

Herbicide Symptomology in Field Crops (Video) – Burke
Abstract: In this video learn about herbicide symptomology in field crops.

Herbicide Timing Poster 2014 (pdf)
Abstract: The timing of herbicide applications in wheat is based on growth stages of the crop and weeds. Applying herbicides according to the labeled stage of growth minimizes crop injury.

How Soil pH Affects the Activity and Persistence of Herbicides (FS189E)
Abstract: Decreasing soil pH, also called soil acidification, is a growing concern in eastern Washington and northern Idaho. Researchers and farmers have measured soil pH values below 5.0 throughout the Palouse region, in particular. Decreasing soil pH has serious implications for the cropping systems of the Palouse.

Herbicide-Resistant Weed Management

Go to Herbicide Resistance Resources

Best Management Practices for Managing Herbicide Resistance (PNW754)

Abstract: Herbicide resistance is a problem that has quickly spread throughout the wheat-growing regions of the inland Pacific Northwest. Over-reliance on herbicides for the management of weeds is a major cause of herbicide resistance. Integrated weed management relies on a wide range of practices to manage weeds and slow the development and spread of herbicide resistance. This publication presents growers and farm managers with best management practices (BMPs) that can be incorporated into farming systems to manage herbicide resistance. A table toward the back of the publication (Table 3) allows readers to identify practices that are already being used and additional practices that should be implemented.

*REVISED MAY 2024* Harvest Weed Seed Control: Applications for PNW Wheat Production Systems (PNW730)
Abstract: Herbicide resistance is of growing concern to wheat growers in the Pacific Northwest (PNW). Harvest weed seed control (HWSC) is an innovative, non-chemical approach developed in Australia that takes advantage of seed retention at maturity in many dominant annual weed species. Harvest weed seed control systems are focused on the management of chaff material in which most weed seed resides. Although HWSC has not been fully evaluated in the PNW, early work suggests that it can be an effective tool in an integrated weed management program. The choice of which particular HWSC system to use is dependent on the constraints of the cropping systems in which they are used and the specific needs of the grower. This publication discusses the various HWSC systems and their potential suitability for PNW wheat production systems across rainfall regions.

Herbicide-Resistant Weeds and Their Management (PNW437)
Abstract: Herbicide resistance is the inherited ability of a plant to survive a herbicide application to which the original populations were susceptible. Resistant plants occur naturally within a population. They differ slightly in genetic makeup from the original populations, but they remain reproductively compatible with them.

Management Strategies for Preventing Herbicide-Resistant Grass Weeds in Clearfield Wheat Systems (PNW572) (pdf)
Abstract: The Clearfield (imidazolinone-resistant) winter wheat production system is currently available in the Pacific Northwest. Imazamox (Beyond), a group 2 (ALS inhibitor) herbicide, applied to Clearfield winter wheat provides an unprecedented opportunity to selectively control jointed goatgrass. The system can also be used to control other grass weeds, such as downy brome and wild oat.

Strategies to Minimize the Risk of Herbicide-Resistant Jointed Goatgrass (EM024E)
Abstract: The purpose of this publication is to provide information about jointed goatgrass and its control with an emphasis on the prevention and management of herbicide resistance.

REACCH (Regional Approaches to Climate Change)

Advances in Dryland Farming in the Inland Pacific Northwest – Ch. 9: Integrated Weed Management
Abstract: Integrated weed management (IWM) strategies are critical for effective long-term management of weeds in the agroecosystem. Knowledge of weed biology is critical for successful long-term IWM, as is the integration of multiple methods of weed management. Methods of weed management include preventative, mechanical, cultural, and chemical inputs. Weed managers should develop a management plan that incorporates knowledge of weed biology, consideration of inputs, and effective method evaluation. A good competitive crop will always be the best weed management practice, and a sequence of successful crop rotations are critical for managing weeds in the inland Pacific Northwest (PNW).

Downy Brome Management Under Future Climate Scenarios (pdf)
Abstract: Downy Brome (Bromus tectorum) is an invasive winter annual grass species, widespread throughout the winter wheat production regions of the PNW. Physiological development of downy brome occurs earlier in the season than does that of other winter annual grasses.

For more information, visit reacchpna.org

STEEP (Solutions to Environmental & Economic Problems)

PNW Weed Management Handbook

This handbook is designed as a quick and ready reference for weed control practices and herbicides used in various cropping systems or sites in Idaho, Oregon, and Washington.