Charcoal Rot of Corn
Published: 01/27/2022
Charcoal rot is caused by the fungus Macrophomina phaseolina. The pith and rind of affected plants appear gray because of the numerous tiny black microsclerotia that develop. The pith tissue is disintegrated, leaving the vascular tissue with a granular, gray appearance.
The fungus overwinters as sclerotia in crop residue and soil and infects plants through roots. It may occur when growing conditions are hot and dry.
Crop rotation is usually not effective because sclerotia can survive more than one year in soil, and other crops such as soybean and alfalfa are hosts.
Numerous microsclerotia produce the "charcoal-like" appearance of tissue characteristic of charcoal rot.
Image: G. Munkvold
Charcoal rot causes disintegration of pith tissue as well as formation of microsclerotia.
Image: G. Munkvold
Charcoal rot causes disintegration of pith tissue as well as formation of microsclerotia.
Pith tissue disintegrates, leaving vascular tissue granular and gray.
Numerous microsclerotia produce the 'charcoal-like' appearance charcoal rot.
Pith of affected plants appears gray because of numerous tiny black microsclerotia.
Charcoal rot may occur when conditions are hot and dry.
Pith disintegration and microsclerotia characteristic of charcoal rot.
Gallery Images: 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.
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.
