Pythium Root Rot of Wheat
Published: 03/19/2019
Pythium root rot is a soil-borne disease that reduces yield in wheat growing regions throughout the U.S. and Canada. It is caused by Pythium spp. and Globisporangium spp. Symptoms include stunting, yellowing, tiller reduction, and poor stand. Symptoms are generally more noticeable in low lying areas. Infected roots are shorter, have few root hairs, and are necrotic. The outer layer of the root (the cortex) falls off easily. Symptoms can be observed from seedling stage to ripening.
The outer layer of the root (the cortex) of Pythium-infected plants falls off easily.
Image: M. Burrows
Outer layer of root tissue missing on plant with Pythium root rot.
Image: M. Burrows
Cool, wet, poorly-drained soils favor Pythium root rot. Fields that retain moisture, such as those with heavy soils or crop residue on the surface, will be at greater risk for disease development.
Disease risk can be reduced by selecting a planting date that avoids cool, wet soil. Residue management allows soil to warm and dry more quickly in spring. Fungicide seed treatments are labeled for Pythium, but effectiveness is limited to the first few weeks after planting.
Cool, wet, poorly-drained soils favor Pythium root rot.
The outer layer of the root (the cortex) of Pythium-infected plants falls off easily.
Gallery image: M. Burrows.
This publication was developed by the Crop Protection Network, a multi-state and international collaboration of university/provincial extension specialists and public/ private professionals that provides unbiased, research-based information to farmers and agricultural personnel. This information in this publication is only a guide, and the authors assume no liability for practices implemented based on this information. Reference to products in this publication is not intended to be an endorsement to the exclusion of others that may be similar. Individuals using such products assume responsibility for their use in accordance with current directions of the manufacturer.
In accordance with Federal civil rights law and U.S. Department of Agriculture (USDA) civil rights regulations and policies, the USDA, its Agencies, offices, and employees, and institutions participating in or administering USDA programs are prohibited from discriminating based on race, color, national origin, religion, sex, gender identity (including gender expression), sexual orientation, disability, age, marital status, family/parental status, income derived from a public assistance program, political beliefs, or reprisal or retaliation for prior civil rights activity, in any program or activity conducted or funded by USDA (not all bases apply to all programs). Remedies and complaint filing deadlines vary by program or incident.
Persons with disabilities who require alternative means of communication for program information (e.g., Braille, large print, audiotape, American Sign Language, etc.) should contact the responsible Agency or USDA's TARGET Center at (202) 720-2600 (voice and TTY) or contact USDA through the Federal Relay Service at (800) 877-8339. Additionally, program information may be made available in languages other than English.
To file a program discrimination complaint, complete the USDA Program Discrimination Complaint Form, AD-3027, found online at How to File a Program Discrimination Complaint and at any USDA office or write a letter addressed to USDA and provide in the letter all of the information requested in the form. To request a copy of the complaint form, call (866) 632-9992. Submit your completed form or letter to USDA by: (1) mail: U.S. Department of Agriculture, Office of the Assistant Secretary for Civil Rights, 1400 Independence Avenue, SW, Washington, D.C. 20250-9410; (2) fax: (202) 690-7442; or (3) email: program.intake@usda.gov.
USDA is an equal opportunity provider, employer, and lender.
©2024 by the Crop Protection Network. All rights reserved.
