MN Fruit & Vegetable IPM News - Vol. 1, No. 9

European corn borer (ECB): The first ECB flight continues to remain low throughout most of the state, and is declining in those areas that did report higher moth catches (see graph). Degree days for ECB as of July 6 were at 950, so the ECB flight should be ending within the week. We would not expect the start of the 2nd flight until approximately 1400 DD. For more information on ECB, see the June 7 issue of the newsletter at http://www.vegedge.umn.edu/MNFruit&VegNews/Vol1/vol1n5.htm.

Corn earworm (CEW): We continue to see very low CEW trap catches across the state. For additional information see the 2004 Moth Flight site for up-to-date information on moth flights. Low CEW moth flights, at this time of year, are normal for Minnesota. In most years (8 of 10 years), we do not have significant flights until early to mid August, with first detection occurring along the Iowa/Minnesota border and southern counties of MN. Because of this timing, the primary annual risk of CEW damage is usually limited to late-planted sweet corn. However, this year, with several delays in sweet corn plantings, and recent cooler weather, we are concerned that more sweet corn in Aug-Sept. may be vulnerable to CEW. We will continue to watch the trap network closely and advise.

Potato Leafhopper (PLH): PLH has now reached treatable levels in snap beans this week at Rosemount, MN. The current threshold is 0.5/sweep during the unifoliate to 3 rd trifoliate growth stages, and 1/sweep during growth stages beyond 3rd trifoliate.

In nearby alfalfa, PLH is at 0.5/sweep, which is up from last week (0.2/sweep). However, there are still no PLH nymphs present in the field, so populations can change rapidly.

Bean leaf beetle (BLB): Overwintering populations continue to decline. Very few beetles can be found in snap beans. The next generation should start to appear around mid-August; maturing snap bean fields should be watched for foliar as well as pod feeding.

Cabbage looper (CL): Despite our trap catches remaining low over the last week, we found 10-25% of cabbage plants infested with cabbage loopers at Rosemount, MN. The current threshold is 10% of plants infested with one or more cabbage looper larvae (young, early-instar larvae; up to ¼ inch). Treatments should be applied when larvae are small.

Return to index

ACKNOWLEDGEMENTS

Co-Editors: Bill Hutchison, Department of Entomology, University of Minnesota, hutch002@umn.edu
Jeanne Ciborowski, Minnesota Department of Agriculture, Ag. Resources Division,jeanne.ciborowski@state.mn.us
Suzanne Wold-Burkness, Department of Entomology, University of Minnesota, woldx018@umn.edu

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., Tuesday to Jeanne Ciborowski, 651-297-3217, jeanne.ciborowski@state.mn.us , MDA, 90 W. Plato Blvd., St. Paul, MN 55107-2094. 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: www.mda.state.mn.us/biocon/fruitreports/default.htm

Partial funding for this publication is provided through partnership agreements with the Minnesota Fruit and Vegetable Growers Association and the United States Department of Agriculture – Risk Management Agency (RMA) and the RMA Community Outreach and Assistance Partnership Program. These institutions are equal opportunity providers.

DISCLAIMER

References 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.

Last Revised July 8, 2004.
The University, including the Minnesota Extension Service, is an equal opportunity educator and employer. ©1999-2004 Minnesota Extension Service, University of Minnesota. All rights reserved. Contact copyright@extension.umn.edu for information on reproduction or use of this material.