Sweet Corn Insect Pest Update

Bill Hutchison and Eric Burkness, Dept. of Entomology, University of Minnesota, St. Paul, Minn.

The corn earworm (CEW) moth flight really took off this week in southern Minnesota, with moth captures in pheromone traps exceeding 200/night (up to 700/night on 8/15) in the far south-central locations (Faribault county/Iowa border). Near the Twin Cities area, we are still averaging 30-50/night. (see graph). Dr. John Wedberg, University of Wisconsin-Madison, also reported a significant increase at the Arlington, Wisconsin research farm of approx. 50/night (for August 14-15th). With these numbers, previous experience (and data) indicates a very high probability of mating and egg-lay on attractive crops, such as silking sweet corn and flowering snap beans.

Meanwhile, the European corn borer (ECB) flight declined at some locations the past few days. This decline is in line with our 2nd generation degree-day model that shows peak activity at 1800 DDs; we are now at 2000 DDs for much of southern Minnesota. This model works well for the FIRST ECB peak 2nd generation flight. In a "high-pressure" ECB year, we can also have a more extended 2nd generation flight, or a possible 3rd generation flight. Thus, far the ECB year is shaping up to be very similar to 1999, with slightly higher moth counts this year.

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 August 16, 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.