Frost Injury in Soybean
Air temperatures below 32℉ may injure soybean leaves, and temperatures below 30℉ may cause injury to both stems and pods. Temperatures at or below 28℉ are considered a killing freeze and may cause premature death in soybeans depending on the length of the freeze, stage of the crop, and low temperature reached. Late-season frost/freeze of soybean will reduce seed size, ultimately reducing yield and seed quality.
Frost occurring early in the growing season.
Tristan Mueller
Frost occurring later in the growing season.
Tristan Mueller
Symptoms of early-season frost injury include seedlings with water-soaked or discolored hypocotyls. When this occurs, seedlings are likely dead. Plants with upper leaf damage will recover if the growing point or axillary buds are still alive and showing new growth in the few days following the frost. Early season frost damage may be confused with seedling disease.
Symptoms of late-season frost injury include wilted plants and leaflets that may die and drop off prematurely if they are entirely frozen. This may be confused with anthracnose stem blight, charcoal rot, stem canker, and white mold if the leaves are still attached to the main stem.
Frost injury may take several days to assess. Soybeans should be observed three to five days after frost for signs of renewed or continued growth. Consider replanting if the stand is reduced sufficiently and it is still early enough in the season to do so.
Prepared and reviewed by the Science for Success team and the Integrated Pest Management Program at Iowa State University.
Soybean seedlings injured by frost.
Soybean plants injured by frost later during the growing season.
Soybean seedling injured by frost.
Soybean plants injured by frost later during the growing season.
Soybean plants injured by frost later during the growing season.
Gallery images courtesy Tristan Mueller.
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.
