In this Issue:
VEGETABLE NEWS
European Corn Borer Flight Ready for Take-off
STRAWBERRY NEWS
Strawberry Weekly Pest Sampling Data
APPLE NEWS
| Vol 3 No. 4 | June 2, 2006 |
European Corn Borer Flight Ready for Take-off
Bill Hutchison, Dept. of Entomology, University of Minnesota, St. Paul, Minn.
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With the warm Memorial Day weekend, locally overwintered European Corn Borer (ECB) rapidly gained >100 degree-days (heat units) throughout southern Minnesota. On May 30th, Eric Burkness recorded the first ECB moth for the year at Rosemount (Dakota Co.). This catch is right on track with the ECB Degree-day model, validated with previous years of MN spring weather (see graph, below). However, because of variable and cool weather, emergence is typically erratic during the 1st flight. For example, a bi-modal pattern of emergence will be observed when periods of cold or rainy nights occurs between warm, favorable nights for moth flight. We are currently at about 422 degree-days (degree-days > 50F), which is near the beginning of the first flight (graph, below). |
Peak flight occurs at 50% "Cumulative Moth Capture" (see 0.5 on graph), which is approximately 600 degree-days. Please review the ECB forecast graph, for expected emergence, and follow upcoming issues of the newsletter for ECB and degree-day updates. With the recent warm days, and nights, corn should also be taking off; some of the early planted sweet corn is in the 3-4 collar stage (Rosemount) this week. All early-planted sweet corn, with extended leaf height at least 17" and/or corn in the early green tassel stage will be most attractive for egg-lay. These fields should be watched closely. Because relatively few fields of field or sweet corn will likely be attractive for egg-lay, the early planted sweet corn is often a major magnet for early infestations. All light-trap cooperators should have their traps up and running for the year.
Reminder: View and bookmark the Moth Flight web page to track the 2006 ECB and Corn Earworm flights this summer.
Beware of the "UCB" (Univoltine Corn Borer): The model presented in this article applies only to growing regions where the dominant ECB strain is the "bivoltine" (2-generation/year) ecotype. However, during the past 10 years, we have also observed a continued increase in univoltine activity (same ECB species, but single generation/year) in southern Minnesota, and eastward spread across southern Minnesota. In 2002, we observed a significant univoltine flight at Rosemount. In many areas of southern Minnesota (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 (i.e., late June to late 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 keep you abreast of significant flights of the Univoltine strain of ECB.
ACKNOWLEDGEMENTS
Co-Editors: Bill Hutchison (hutch002@umn.edu), Department of Entomology, University of Minnesota, Jeanne Ciborowski, Minnesota Department of Agriculture, Ag. Resources Management and Development Division, and Suzanne Wold-Burkness (woldx018@umn.edu), 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 Jean Ciborowski, 651-201-6217, jeanne.ciborowski@state.mn.us, MDA, 625 Robert St. North, St. Paul, MN 55155-2538. You can access the Newsletter at the U of MN web site in htm format at: www.vegedge.umn.edu/MNFruit&VegNews/mnindex.htm and at the MDA web site in pdf format at: http://www.mda.state.mn.us/ipm/ipmnews/
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.
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