Phyllosticta Leaf Spot of Soybean
Published: 03/19/2019
Phyllosticta leaf spot is caused by the fungus Phyllosticta sojicola. Lesions most often occur on leaves and are circular, oval, and irregular or V-shaped. Lesions appear gray or tan and have a narrow, dark margin. In older lesions, numerous small, black specks (i.e., pycnidia) may be visible.
The fungus likely survives in infested crop residue and can be seed transmitted. Cool, moist conditions favor disease development.
Crop rotation and tillage will reduce survival of the fungus.
Phyllosticta leaf spot lesions.
Image: D. Mueller
Small, black pycnidia may be observed in older lesions.
Image: A. Sisson
Small, black pycnidia may be observed in older Phyllosticta leaf spot lesions.
Magnified view of Phyllosticta leaf spot lesion with pycnidia fruiting structures.
Phyllosticta leaf spot lesions on soybean leaf.
Phyllosticta leaf spot lesions can be circular, oval, and irregular or V-shaped.
Phyllosticta leaf spot lesions appear gray or tan and have a narrow, dark margin.
Phyllosticta leaf spot lesions on soybean leaf.
Small, black pycnidia may be observed in older Phyllosticta leaf spot lesions.
Phyllosticta leaf spot lesions can be circular, oval, and irregular or V-shaped.
Phyllosticta leaf spot lesions on soybean leaf.
Phyllosticta leaf spot lesions on soybean leaf.
Phyllosticta leaf spot lesions on soybean leaf.
Phyllosticta leaf spot lesions on soybean leaf.
Phyllosticta leaf spot lesions on soybean leaf.
Phyllosticta leaf spot lesions on soybean leaf.
Gallery Images: 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.
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.
