Fusarium Head Blight of Wheat
Published: 03/19/2019
Fusarium head blight (FHB) is currently the most economically important wheat disease in the U.S. and Canada. This disease is also known as scab or head blight and is caused by Fusarium graminearum and other Fusarium spp. It reduces yield and produces mycotoxins that impact human and animal health. Infected spikelets are bleached and disease spreads upward and downward by sequentially infecting spikelets. Pink or orange spore masses can sometimes be observed on infected spikelets, particularly at the base. Small, dark fruiting structures may also be present on spikelets. Infected kernels become shriveled, chalky, and can be discolored white-pink. These "tombstone" kernels are lightweight and highly contaminated with mycotoxins. Tombstone kernels often blow away with chaff.
Infected spikelets are bleached and disease spreads upward and downward by sequentially infecting spikelets.
Image: M. Burrows
Pink or orange spore masses can sometimes be observed on infected spikelets, particularly at the base.
Image: C. Grau
The pathogen can survive on infected host residue. Warm, wet weather with high relative humidity during flowering (anthesis) and early grain formation favors disease development. Use //www.wheatscab.psu.edu to evaluate disease risk in your location.
Moderately resistant wheat varieties are available. Encourage decomposition of plant residue through tillage when possible, rotate away from a host crop (corn or small grains) for at least one year, and plant high-quality, disease free seed. Properly adjust combines to help discard lightweight, moldy kernels, and to reduce damaged kernels, which are more susceptible to mold. Fungicides, primarily triazoles (FRAC group 3), are labeled for FHB. Application is recommended when favorable conditions for FHB exist prior to and throughout heading. The best application timing is early flowering (FGS 10.51), but application up to 7 days after initiation of flowering can reduce FHB and mycotoxin contamination. Do not use QoI (strobilurin; FRAC group 11) fungicides as these can increase mycotoxins. Harvest fields with FHB separately and avoid mixing contaminated and non-contaminated grain. Store moldy grain appropriately to minimize impact on grain quality. Molded grain or silage should be tested for mycotoxins prior to feeding.
For more information see the Optimizing Fungicide Use for Fusarium Head Blight (Scab) and Associated Mycotoxins publication.
Pink or orange spore masses can sometimes be observed.
Bleaching of spikelets symptomatic of Fusarium head blight.
Infected wheat spikelets are bleached.
Disease spreads upward and downward sequentially infecting spikelets.
Infected kernels are shriveled, chalky, and can be discolored white-pink.
Fusarium head blight bleaching can occur on single spikelets and spread.
Pink or orange spore masses can sometimes be seen on spikelets.
Fusarium head blight reduces yield and mycotoxins are produced.
Gallery images: E. Byamukama, M. Burrows, A. Friskop, and C. Grau.
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.
