Sweet Corn Insect Pest Update

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

The Corn earworm (CEW) flight continued to remain high in some of the southern locations, with slight reduction in moth catch, to moderate numbers, at Rosemount, and at John Wedberg’s trap at Arlington WI (48/trap/night). All susceptible fields should continue to be protected with insecticide. Once sweet corn has reached the brown silk stage, and/or is within 7-10 days of harvest, additional treatments are not necessary (if one of the previously mentioned pyrethroids has been used, beginning at first silk or row tassel). Same treatment consideration should be used for ECB (below).

European corn borer (ECB) moth flight continued to taper off this past week. Now at approximately 2100 Degree-days (southern Minnesota) the 2nd generation flight should be approx. 80-90% complete; i.e., moth emergence for a given location. However, some moths can still move in from other locations, and we can also have more extended flights in a given area, due to developmental delays resulting from mating or oviposition interruptions during the first flight.

For those with web access, continue to check the following sites for the most recent moth flight data, for:
CEW: http://www.vegedge.umn.edu/CEWTRAPS/CEW2000.htm
ECB: http://www.vegedge.umn.edu/ecbmap/MN2000.htm

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

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Last Revised August 25, 2000.
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