Diplodia Stalk Rot of Corn
Published: 03/19/2019
Diplodia stalk rot is caused by the fungus Stenocarpella maydis. Plants affected by Diplodia stalk rot have shredded pith and die prematurely. Numerous black dots, about the size of a pinhead or smaller, can be observed in the lower internodes of the stalk. Under very wet conditions, a white mold may develop on the stalk surface.
Infections occur through the crown, roots, mesocotyl, and lower nodes. Insects possibly carry the spores and introduce them into feeding wounds. Diplodia stalk rot is favored by dry conditions early in the season followed by warm, wet conditions after silking. The disease is more prevalent in corn following corn.
There are hybrids available with good resistance to Diplodia stalk rot. Rotation and tillage can reduce inoculum.
Shredded pith from Diplodia stalk rot.
Image: A. Robertson
Diplodia stalk rot can result in small black pycnidia on the lower internodes that are not easily scraped off.
Image: G. Munkvold
Signs of Diplodia stalk rot include pycnidia on lower internodes.
Shredded pith from Diplodia stalk rot.
Pycnidia, a fungal fruiting structure, cannot easily be scraped off.
Small, black pycnidia on the stalk cannot easily be scraped off.
Stalk lodging from Diplodia stalk rot.
Diplodia stalk rot can result in small black pycnidia on the lower internodes.
Gallery Images: A. Robertson and G. Munkvold
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.
