In this Issue:

Upcoming Events

VEGETABLE NEWS

Vegetable Insect Summary for Minnesota - 2006: European corn borer and Corn earworm

GRAPE NEWS

Wine Grape Insect Summary for Minnesota and Northwestern Wisconsin - 2006: Beetles & Moths

STRAWBERRY NEWS

Fall Colors, Plant Health and Weed Control

APPLE NEWS

The USDA Cooperative Agricultural Pest Survey for Exotic Apple Pests in Minnesota

Dogwood Borer in Minnesota

IPM PUBLICATION

New IPM Publication Series for Growers, Processors, Crop Consultants, & Extension Educators

Insect, Pest Fact Sheets

Vegetable Insect Summary for Minnesota - 2006: European corn borer and Corn earworm

Bill Hutchison, Eric Burkness, Dept. of Entomology, University of Minnesota, St. Paul 55108

European corn borer (ECB) populations in Minnesota , based on moth catch data for several southern Minnesota locations (see Fig. 1), were again low for most locations. The trend for relatively low ECB flights, and subsequently, low larval infestations in sweet and field corn, has been consistent for much of southern Minnesota since 2000. For most of southern Minnesota , the traditional two-generation strain of ECB (bivoltine) continues to be the most common strain, with generations peaking in June and August, respectively. However, as noted at Lamberton, and several locations in 2006 (including the past 8-10 years), there continues to be evidence for the single-generation strain (univoltine), which is active throughout most of July. For areas with significant sweet corn production, the presence of both strains results in essentially continuous moth flights, and oviposition on susceptible crops.

Additional information, including a figure summarizing the 50-year trend in ECB fall survey data, as compiled by Mark Abrahamson of the MDA Pest Survey group, see the Minnesota Pest Report page (PDF files) at the MDA site:(The Annual Summary Report for 2006 should be available later this year, or by January, 2007.)

For more information regarding the ECB trends, you may also review the 2005 Summary article in this newsletter (Sept. 30, 2005).

Corn earworm (CEW) moth flights, as measured by ‘Hartstack' wire-mesh pheromone traps, were much higher in 2006, for most southern Minnesota locations, compared to the past 3-4 years. Moth flight data for 2006 are summarized in Fig. 2. Even with the CEW flight peaking at only 180 moths/night at Rosemount (Dakota Co.), in late August, approx. 90% of the ears were infested (1 or 2 larvae/ear) at the Sept. 15^th harvest (Table 1). For the flights peaking at 800-900/night, in the Blue Earth and Dodge Center locations, sweet corn and susceptible crops should have received a significant egg-lay and larval infestation. Additional data sets summarizing the relationship between planting date, harvest date and subsequent larval infestations in sweet corn ears were summarized for multiple planting data sets for 2005 and 2006, Rosemount, MN (Table 1).

As most of you know, we were also active this year in monitoring for susceptibility/resistance to the pyrethroid insecticides in CEW. This effort was made possible by new funding and considerable cooperation among many university research and extension personnel, as well as industry representatives. To date, however, much of the data continue to be analyzed from this past summer, including resistance monitoring and field efficacy data from multiple states. Thus, the “jury is still out” regarding how we will characterize the resistance concern this year, and develop alternative recommendations for 2007. When new recommendations are developed, they will be published in this newsletter and similar Vegetable IPM Newsletters for the Midwest Region.

Further Reading:

For more information regarding the incidence of all major crop insect, disease and weed pests in Minnesota (PDFs), visit the MDA Pest Report page.

For additional information regarding the relationship of CEW pheromone trap catches, and the relationship of the percentage of ears infested with larvae and larval density per ear, see the June 30^th 2006 article.

THANKS AGAIN!

…to all of the volunteers and associate industry personnel who maintained light traps, pheromone traps, and conducted in-field monitoring. Your efforts help keep the newsletter timely and relevant.

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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.

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 manufacturer directions.

The University, including the Minnesota Extension Service, is an equal opportunity educator and employer. ©1999-2006 Minnesota Extension Service, University of Minnesota. All rights reserved. Contact copyright@extension.umn.edu for information on reproduction or use of this material.