Purple Seed Stain of Soybean
Published: 01/27/2022
Purple seed stain is caused by the fungus Cercospora kikuchii. Seeds infected with this pathogen can be symptomless or have pink to purple spots extending from the hilum. Discoloration can cover the entire seed or appear as small spots.
Crop value may be lowered by dockage or seed certification denial, but yield is not reduced.
Purple seed stain incidence can be increased by warm, wet weather during and after flowering.
Although caused by the same organism, there is no consistent relationship between occurrence of Cercospora leaf blight and purple seed stain.
Purple seed stain symptoms on soybean seed.
Image: T. Mueller
Purple seed stain symptoms on soybean seeds.
Image: A. Sisson
For more information see the Soybean Seed Quality Considerations feature article.
Purple seed stain symptoms on soybean seed within the pod.
Warm, wet weather during and after flowering can increase purple seed stain.
Purple seed stain discoloration can cover the entire seed or appear as small spots.
Early symptoms of purple seed stain.
Purple seed stain symptoms on soybean seed in the field.
Infected seeds have pink to purple spots extending from the hilum.
Gallery Images: T. Mueller, D. Mueller, and A. Sisson
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.
The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and activities on the basis of race, color, national origin, age, disability, and where applicable, sex, marital status, familial status, parental status, religion, sexual orientation, genetic information, political beliefs, reprisal, or because all or a part of an individual's income is derived from any public assistance program. (Not all prohibited bases apply to all programs.) Persons with disabilities who require alternative means for communication of program information (Braille, large print, audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice and TDD). To file a complaint of discrimination write to USDA, Director, Office of Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or call (800) 795-3272 (voice) or (202) 720-6382 (TDD).
USDA is an equal opportunity provider and employer.
©2022 by the Crop Protection Network. All rights reserved.
