Lesser Cornstalk Borer in Soybean
Crop Damage: Lesser cornstalk borers (Elasmopalpus lignosellus) occur across the southern U.S. states and along parts of the eastern coast. Larvae bore into soybean stems at the plant base, causing wilting, lodging, or death of young plants. As larvae grow, they develop silken tubes on the soil surface that provide protection and a pathway to nearby soybean plants.
Pest Description: Young larvae are yellow-green, while full grown larvae reach about ¾ inch long and have distinct alternating light and dark bands. Adults are small moths with narrow front wings. Female forewings are nearly black, whereas male forewings are light brown.
Lesser cornstalk borer larva in stem.
David Riley, University of Georgia, Bugwood.org
Lesser cornstalk borer adult.
John French, Bugwood.org
Scouting: Lesser cornstalk borer can be more problematic when conditions are dry, if soils are sandy, and where reduced tillage or late planting occurs. Begin scouting early in the season, especially in areas with poor emergence or slow plant development. Damage can resemble that of other soil pests such as seedcorn maggots or wireworms, so accurate identification is critical. Dig along rows with poor emergence and examine plants throughout the row, as larvae move to new plants while feeding. Dissect plants to check for tunneling in the stem, and look for larvae in silken tunnels that may be present in and around dead plants.
Lesser cornstalk borer silken tube.
Steve Brown, University of Georgia, Bugwood.org
Management: No rescue treatment currently exists for lesser cornstalk borer in soybean. Insecticide treatments may be considered if 10% or more of seedlings are infested, and replanting may be necessary in severe cases. Adjust tillage practices or planting dates if this pest becomes persistent in a field.
Developed and reviewed by Carol Pilcher, Iowa State University and Robert Wright, University of Nebraska-Lincoln, with support from the United Soybean Board.
A lesser cornstalk borer larva in stem. The larva has destroyed stem tissue and is dark with white stripes. Image by David Riley, University of Georgia, Bugwood.org.
A lesser cornstalk borer adult on a green leaf. The moth appears slender and light brown in this image. Image by John French, Bugwood.org.
A lesser cornstalk borer silken tube attached to a plant stem. Image by Steve Brown, University of Georgia, Bugwood.org.
Gallery images courtesy Steve Brown, University of Georgia, Bugwood.org; David Riley, University of Georgia, Bugwood.org; and John French, Bugwood.org.
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, 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 State or local Agency that administers the program or contact USDA through the Telecommunications Relay Service at 711 (voice and TTY). 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, Mail Stop 9410, Washington, D.C. 20250-9410; (2) fax: (202) 690-7442; or (3) email: program.intake@usda.gov.
This work is supported by the Crop Protection and Pest Management Extension Implementation Program from the U.S. Department of Agriculture’s National Institute of Food and Agriculture. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and should not be construed to represent any official USDA or U.S. Government determination or policy.
USDA is an equal opportunity provider, employer, and lender.
©2025 by the Crop Protection Network. All rights reserved.
