European Corn Borer 2000

Bill Hutchison, Extension Entomologist, University of Minnesota

For those who are participating in the annual (and primarily voluntary) black-light trap network in Minnesota, now is the time to get your traps out. The first-generation flight for European corn borer (ECB) should be underway... if not now, in the next few days. Figure 1 illustrates the timing (phenology) of the first ECB moth flight, as function of degree-days (DDs >50F) for the Rosemount Agric. Expt. Station site (Dakota Co.), just southeast of the Twin Cities. As shown this is based on 8 years of data, and worked well for forecasting key flight events in 1999. For example, the peak of the flight occurs at 50% "Cumulative Moth Capture" (0.5 on graph), occurs at 600 DDs. Hopefully, we will have a similar graph in place for the 2nd gen. flight. As of today, we are currently at approx. 450-500 DDs for much of southern WI and MN (see WI/MN web site below).

Note: This graph applies only to growing regions where the dominant ECB strain is the "bivoltine" (2-generation/yr) ecotype. In many areas of southwestern to south-central Minnesota (and as in northwestern MN), the univoltine (1 gen/yr) strain is dominant, or becoming more common. With the univoltine strain, the flight comes out 2-3 weeks later than the first flight of the bivoltine; the flight is also somewhat extended, occurring roughly from mid-June through July. In south-central MN, where both strains occur, this can create an insect management nightmare, where sweet corn and other crops can essentially be vulnerable to larval infestations throughout the summer. As the summer progresses, we will have more information about the current distribution of each strain in Minnesota. The WI/MN web site, noted below, is an excellent way to track the current Degree-day accumulations for ECB, for both MN, WI (and northern IA). The site is automatically updated daily! Please bookmark this site in your web browser, for rapid updates: http://bob.soils.wisc.edu/wimnext/corn/euroborer.html (The site also provides additional ECB biology, key events, etc. relative to DDs).

If you would like additional background information on Degree-days, and their value to crop and insect forecasting, check out the Iowa State Newsletter article:

http://www.ipm.iastate.edu/ipm/icm/1998/4-6-1998/dd.html

Co-Editors:Bill Hutchison, Department of Entomology, University of Minnesota, hutch002@tc.umn.edu
Jeanne Ciborowski, IPM Program, Minnesota Department of Agriculture, jeanne.ciborowski@state.mn.us
Cindy Tong, Department of Horticulture, University of Minnesota, ctong@extension.umn.edu
Production Editor: Suzanne Wold, Research Specialist, University of Minnesota, woldx018@tc.umn.edu

Disclaimer
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 directions of the manufacturer

Last Revised May 18, 2000.
The University, including the Minnesota Extension Service, is an equal opportunity educator and employer.©1999 Minnesota Extension Service, University of Minnesota. All rights reserved. Contact copyright@extension.umn.edu for information on reproduction or use of this material.