MN Fruit & Vegetable IPM News - Vol. 1, No. 3

Aster Leafhopper (ALH): ALH has arrived in alfalfa fields. On May 11, populations were at 0.1 ALH adult/sweep. On May 18, populations increased to 1.6 ALH adult/sweep. The upper Midwest receives multiple migrating flights of ALH from southern states each year beginning in mid- to late-May. ALH is olive green with 6 black spots across the head and is a primary pest of carrot, lettuce and celery because of the phytoplasma disease it vectors to these crops. Unlike potato leafhopper (PLH), which we have not yet observed, ALH is NOT a pest of alfalfa. As carrot, lettuce, and celery crops are planted and emerge, monitoring for ALH should begin. For more information on controlling ALH in carrots, see the fact sheet at: http://www.vegedge.umn.edu/vegpest/aster.htm. For more information regarding the identification of Aster vs. Potato Leafhopper, see our May 2002 article at: http://www.vegedge.umn.edu/mnvegnew/vol4/524pot.htm

Bean Leaf Beetle (BLB): As noted in the previous issue, BLB activity was minimal. Within a few days after the emergence of our first snap bean plots, we found BLB adults and associated damage. On May 18, BLB populations ranged from 0.25-0.50 BLB/plant. Individual plants were found to have up to 6 BLB/plant. The growth stages in our field ranged from cotyledon to unifoliate. Monitoring should begin at crop emergence and control should be considered if more than 10% of the seedlings in the cotyledon to first trifoliate stages exhibit more than 25% defoliation (e.g., 6-10 "shot-holes" per leaf).

For more information, see the fact sheet at: http://www.vegedge.umn.edu/vegpest/BLB.htm

Seed Corn Maggot (SCM): SCM infestations were found on May 17 in snap beans planted on May 3. Evaluations of insecticide seed treatments on May 19 indicated that in plots where seed was treated with only a fungicide, 58% of seedlings had seed corn maggot damage. Insecticide seed treatments, such as Cruiser, Gaucho, and Lorsban, reduced plant damage caused by SCM (data continue to be analyzed). SCM larvae are currently late instar, and should pupate in the soil within the next week. We are currently at approximately 680 degree days (base 39F). The peak flight of the second generation adults should occur at 1,170 degree days. For Rosemount (south-central MN), the peak of the second generation typically occurs during the first week of June. Therefore, in-furrow soil insecticides, or insecticide seed treatments may be warranted for early June plantings of snap beans.

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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.

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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 May 21, 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.