Plant diseases

Several statewide and regional programs are in place to help with your plant diseases. The OSU Plant Clinic can help you diagnose the problem while the PNW Plant Disease Management Handbook can help with solutions. Several OSU faculty are located throughout the state to also assist with plant problems.

PNW Plant Disease Management Handbook

By Jay W. Pscheidt and Cynthia M. Ocamb

A comprehensive guide to plant disease management in the Pacific Northwest.

Includes materials and tactics suitable for organic production and homeowner use as well as for commercial production.

View publication

Photo Credit: Firn - Adobe Stock (Cropped from original)

Featured Resources

Biology and Management of Beet Leafhopper and Purple Top in Potatoes in the Pacific Northwest

Leafhoppers damage potatoes by feeding on the plants, or by transmitting viruses and phytoplasmas, which are small bacterial parasites of plant phloem tissue. Phytoplasmas cause purple top disease, which reduces yield ...

Silvia I. Rondon, Tiziana Oppedisano | Apr 2020 | Extension Catalog publication Peer reviewed (Orange level)

Field Guide for Diagnosing Common Wheat Maladies of the Pacific Northwest

This field guide provides an overview of basic plant pathology concepts that are relevant to disease identification in wheat. It introduces tools to help distinguish between biotic and abiotic injuries, and discusses...

Christina Hagerty, Richard Smiley | Sep 2017 | Extension Catalog publication Peer reviewed (Orange level)

Browse All Resources

Managing Diseases and Insects in Home Orchards

By Jay W. Pscheidt , Heather Stoven , Ashley Thompson , Brooke Edmunds , Nik Wiman and Richard Hilton

This pest management guide is for the home gardener. It recommends management practices for controlling diseases and insects in home orchards.

View publication

Photo by Gordon Jones (Cropped from original)

Latest Resources

2024 Pest Management Guide for Wine Grapes in Oregon

Learn the most effective techniques for controlling insects, weeds and disease on wine grapes in Oregon. Study strategies for controlling powdery mildew, botrytis bunch rot and spider mites.

Patricia A. Skinkis, Jay W. Pscheidt, Achala KC, Marcelo Moretti, Vaughn Walton, Cody Copp | Feb 2024 | Extension Catalog publication Peer reviewed (Orange level)

Field crop plant health challenges

This collection offers a thorough examination of the hurdles that plants confront, highlighting a varied group of challenges in agricultural and natural environments. Explore the fundamentals of plant health by delving into topics ...

Mary Corp | Jan 2024 | Collection

Potential new aggressive EFB strain infecting resistant hazelnut varieties

Eastern filbert blight is a fungal disease that has infected many hazelnut orchards in Oregon and Washington. Now some of the resistant varieties are showing signs of infection, notably aggressive cankers. Learn how to identify it, report it and manage it.

Nik Wiman | Dec 2023 | Article Peer reviewed (Gray level)

Browse All Resources

Managing Microdochium Patch in Pacific Northwest Turfgrass

By Clint Mattox , Brian McDonald and Alec Kowalewski

Those round, brown rings that appear on your lawn in spring may just be a passing problem. But if you manage a golf course, you may want to take steps to control Michrodochium nivale, the fungus that causes Microdochium patch on turf grass. To prevent problems, learn how to select the right species of grass, and pick up that rake come fall.

View publication

Photo: Stephen Ward (Cropped from original)

Videos

VIT TECH | Powdery Mildew (April 2022)

Drs. Walt Mahaffee, Research Plant Pathologist for the USDA Agricultural Research Service, and Jay Pscheidt, Extension Plant Pathology Specialist in the OSU Department of Botany and Plant Pathology, share results from current powdery mildew research at the April 2022 VIT TECH session.

Aug 2022 | Video

Bacterial Soft Rot Pathogens of Potato

Jessie Brazil is a Botany and Plant Pathology Masters student at Oregon State University. Jessie does her research at the Hermiston Agricultural Research and Extension Center. The focus is on studying soft rot of potato. This ...

Kenneth Frost, Jessie Brazil | Nov 2019 | Video Peer reviewed (Gray level)

Tackling Potato Virus Y

Tackling Potato Virus Y, a Persistent Problem in Potato Production. Oregon State University Masters student Max Combest explains issues related to Potato Virus Y (PVY). He is doing research of PVY in potato production in the ...

Aymeric Goyer, Max Combest | Oct 2019 | Video Peer reviewed (Gray level)

Eastern Filbert Blight

A fungal canker disease of hazelnut that threatens production in Oregon but can be managed through pruning, fungicides and resistant cultivars.

Jay W. Pscheidt | Mar 2018 | Video

Latest News

Exploring biochar as an alternative sudden oak death treatment

The exploration of various approaches and collaborative problem-solving is a promising approach for future solutions.

Norma Kline, Christopher Adlam | Apr 2024 | Impact story

OSU Extension research helps wheat growers fight serious stripe rust disease

Treatment recommendations accounted for about 65,000 acres of wheat in the region with a net savings to farmers of $2.3 million.

Larry Lutcher, Christina Hagerty | May 2023 | Impact story

OSU Extension outreach helps slow the spread of deadly X-disease in cherries

In the gorge, a survey of 50 orchardists at the 2022 Cherry Day suggests that 86% of those cherry producers can confidently identify X-disease and 48% have removed at least one infected tree since Thompson started her outreach in 2018.

Ashley Thompson, Cody Copp | Apr 2023 | Impact story

All News

Explore more resources

Soil

Integrated pest management

Pesticide safety and education

Meet Our Experts

Jay W. Pscheidt

Professor and Statewide Extension Plant Pathology Specialist

Melodie Putnam

(Retired)

Luisa Santamaria

Nursery Pathology Specialist, Bilingual Educator

Christina Hagerty

Cereal Pathology

Have a question? Ask Extension!

Ask Extension is a way for you to get answers from the Oregon State University Extension Service. We have experts in family and health, community development, food and agriculture, coastal issues, forestry, programs for young people, and gardening.

Ask us a question

Fairy rings in my lawn?

Q: Several brown, dead rings have formed in my lawn this summer. They seem to coincide with a type of mushroom. Are the mushrooms causing this? Is there any treatment short of applying a fungicide that is effective? Will the lawn recover on its own?

A: View answer | View all featured questions

See More Questions