In this Issue:


Section 18 Approved for Coragen

Order: 2008 Minnesota Vegetable Guide

Insect, Pest Profiles

web only edition   July 2, 2008

Section 18 Approved for Coragen (Rynaxypyr) for Corn Earworm Control in Sweet Corn (MN)

Bill Hutchison & Eric Burkness, University of Minnesota

click to enlarge
Multiple CEW larvae on sweet corn

On July 1, 2008, the U.S. EPA approved a Section 18 request to the Minnesota Department of Agriculture (MDA) for use of the insecticide, Coragen™ (DuPont), in the state of Minnesota (similar requests are pending in other midwest states).  A maximum of 40,500 acres may be treated in Minnesota.  Use of Coragen on sweet corn is targeted for late-planted sweet corn that is historically susceptible to migrating CEW moths that cause considerable damage to sweet corn ears.  The Section 18 request was made due to increasing problems with pyrethroid resistance in corn earworm in Minnesota and the Midwest.  In 2007, percent control for all sizes of CEW larvae, for several locations in Minnesota and Wisconsin, averaged 35% using common pyrethroids (bifenthrin and lambda-cyhalothrin).  In recent evaluations, Coragen has provided >90% control of CEW larvae in late-planted sweet corn.  Improved control with Coragen is attributed to a unique mode of action, with muscle tissue receptors.

Processing companies and fresh-market growers should check with their dealers to determine when the product will be available, final pricing, etc.  Although we do not know actual costs for Coragen, it will be more expensive than the pyrethroids.  Final use will depend on overall CEW pressure this year, previous problems with pyrethroids, or other insecticides at your location.  Based on our work the past 2 years, the 5 fl. oz. rate has worked well; however, a surfactant such as MSO must also be included (we have had good results with MSO at 0.5% v/v).   Another consideration, with alternating Coragen with pyrethroids or other materials, is that Coragen should be used for the 1stand 2nd sprays, to ensure maximum CEW control and ear protection.  Coragen is also effective on European corn borer (ECB). There is no need to tank-mix Coragen with pyrethroids or other insecticides.

Use requirements for the Section 18 include:

  • Apply 3.5 – 7.5 fluid ounces (0.045 – 0.098 lb. ai / ac) of product per acre by ground or aerially.
  • A maximum of 2 or 3 applications per season are allowed, depending on rate.
  • A maximum of 15.4 fluid ounces (0.2 lb. ai / ac) of product is allowed per acre per season
  • A 4 hour re-entry interval (REI) is required.
  • The minimum interval between treatments and final application and harvest (PHI) is 1 day.
  • All applicable directions, restrictions, and precautions on the EPA-registered label, as well as those outlined on the Section 18 Emergency Exemption use directions provided with the request, must be followed unless otherwise modified in the Section 18 authorization document.

Follow this link for the Section 18 Emergency Exemption Directions (pdf)


Return to index


Co-Editors: Bill Hutchison (, Department of Entomology, University of Minnesota, Jeanne Ciborowski, Minnesota Department of Agriculture, Ag. Resources Management and Development Division, and Suzanne Wold-Burkness (, Department of Entomology, University of Minnesota

The Newsletter is published weekly from May through August, cooperatively, by the Minnesota Department of Agriculture (MDA) and the University of Minnesota (U of MN).  Reports are posted on the U of MN and MDA web sites on Fridays.  If you have suggestions and/or comments, please send your contributions by 4 p.m., Wednesday to Jeanne Ciborowski, 651-201-6217, , MDA, 625 Robert St. North, St. Paul, MN  55155.  You can access the Newsletter at the U of MN web site in htm format at: and at the MDA web site in pdf format at:

Partial funding for this publication is provided through partnership agreements with the Minnesota Fruit and Vegetable Growers Association (MFVGA) and the United States Department of Agriculture – Risk Management Agency (RMA).  These institutions are equal opportunity providers.


Reference to products in this publication is not intended to be an endorsement to the exclusion of others which may have similar uses. Any person using products listed in this publication assumes full responsibility for their use in accordance with current manufacturer directions.


Last Revised May, 2008 by
The University, including the Minnesota Extension Service, is an equal opportunity educator and employer. Privacy Policy
©1999-2008 Minnesota Extension Service, University of Minnesota. All rights reserved. Contact for information on reproduction or use of this material.