Clover Leaf Weevil in Alfalfa
Crop Injury: Clover leaf weevil (Hypera zoilus) has been present in the U.S. for more than 140 years. Adults and larvae consume alfalfa foliage starting in the lower plant canopy and moving upwards. Leaves with feeding injury appear ragged and severe plant defoliation can occur with high weevil populations. Clover leaf weevil prefers to feed during the night or under cloud cover, retreating to the alfalfa plant base when it is sunny.
Pest Description: Adult weevils are dark brown and speckled with lighter- and darker-colored scales. Adults have a faint stripe on each wing cover and are 5/8 inch in length. Legless larvae have a brown head, are yellow to green with a single white stripe with pinkish borders along the back.
Clover leaf weevil
Whitney Cranshaw, Colorado State University, Bugwood.org
Clover leaf weevil
Whitney Cranshaw, Colorado State University, Bugwood.org
Life Cycle: Overwintering occurs most commonly as larvae or eggs. Larvae become active in late winter to late spring and feed on plants. Cocoons are formed on or near plants, protecting the insect during pupation. Emerging adults consume alfalfa tissue and then become inactive until fall egg laying. Clover leaf weevils have one generation per year.
Scouting: Clover leaf weevil can be confused with alfalfa weevil. Check fields right after the first cutting, especially when weather conditions have been dry.
Management: A fungal pathogen which thrives in warm and wet conditions typically keeps clover leaf weevil populations low. Be aware that weevils may flourish during cool and dry springs, when fungal development is limited. Insecticide application can control clover leaf weevils.
Prepared and reviewed by the Alfalfa Pest Management Working Group.
Clover leaf weevil. Whitney Cranshaw, Colorado State University, Bugwood.org
Clover leaf weevil. Whitney Cranshaw, Colorado State University, Bugwood.org
Gallery images courtesy Whitney Cranshaw, Colorado State University, 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, 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.
