Sweet Corn Insect Pest Updates

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

The European corn borer (ECB) second generation moth flight is officially underway in southern Minnesota. ECB catch approached 90/night at Blue Earth, Minn. Trap catches at Rosemount increased from 2-3/night (late last week) to 25-50/night, on August 1st and 2nd, respectively, for the two traps we maintain at this site (see graph below for selected Minnesota sites). This matches well with the 1665 degree-day accumulation we are now at for Rosemount. Fields in green tassel to open (row) tassel and/or early silk stages will be attractive for egg-lay, and should be scouted carefully for ECB egg masses; the first ECB egg hatch was observed August 1st at Rosemount.

Corn earworm (CEW) moth catch is still very low to nil at all Minnesota locations. Blue Earth and Rosemount sites have averaged only 1-2/week. The primary flight should not begin until approx. August 20th. Beginning next week, a new graph summarizing the CEW flight for several locations will be included in the newsletter.

Corn leaf aphid counts remain moderate to high in 'Jubilee' sweet corn (>25 to >100/tassel), with many several new adults colonizing fields that are either in early (green) tassel, or open (row) tassel growth stages. Although these infestations might cause problems, the early spray for ECB and/or CEW should help suppress populations.

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 8, 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.