Diaporthe Seed Decay of Soybean
Published: 03/19/2019
Diaporthe (formerly Phomopsis) seed decay is caused by the fungus Diaporthe longicolla, and can greatly affect seed quality. Diaporthe-infected seed are cracked and shriveled and are often covered with chalky, white mold. If infected seeds are planted, emergence may be low due to seed rot or seedling blight. Infected seedlings have reddish-brown, pinpoint lesions on the cotyledons or reddish-brown streaks on the stem near the soil line.
Seed that are cracked, shriveled and covered with chalky, white mold may be infected by Diaporthe.
Image: A. Tenuta
Diaporthe-infected soybean.
Image: D. Mueller
Choose varieties with the best resistance package. Tillage and rotation to non-host crops such as corn can reduce inoculum. Timely harvest will help reduce the risk of seed decay and preserve seed quality. Do not plant seed with a high incidence of Diaporthe seed decay. Currently available fungicide seed treatments generally appear to be effective against Diaporthe seed infection. Foliar fungicide applications between R3 and R5 may reduce seed infection especially in seed production fields. Fungicide may improve seed quality, but yield may not be affected.
For more information see the Pod and Stem Blight and Diaporthe Seed Decay publication or the Soybean Seed Quality Considerations feature article.
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.
