MN Fruit & Vegetable IPM News - Vol. 4, No. 1

Despite the slow start to the growing season, we expect that as early planted snap beans and soybeans begin to emerge, bean leaf beetle (BLB) infestations will follow. As was discussed in last spring’s newsletter article, we are still faced with the question of how well we can predict overwintering survival of BLB in Minnesota and can we use that information to better manage pests during the growing season? Based on a Minnesota model for estimating winter survival, which is based on the mean daily temperature from September through April of the next year, we can attempt to predict if populations will increase or decrease relative to the previous year’s population. We are currently compiling data for spring BLB populations that we have from several crops from previous years. With this data, we will try to determine if the populations have increased or decreased, and whether this information is in agreement with the winter survival model that has been developed (see table). According to the model, conditions were more severe this winter and we should expect higher winter mortality, which may lead to lower BLB pressure this spring. Due to numerous other factors that contribute to insect mortality and movement, predicting BLB populations may be difficult based solely on this model; however, it is a step in the right direction and could eventually aid in making pest management decisions in snap beans, especially for insecticidal seed treatments that must be applied to seed without knowledge of whether you will have an infestation or not. We hope to present information on use of the model for predictive purposes in next week’s newsletter and we will continue to monitor populations in the field.

Predicted overwintering mortality of BLB for select locations in MN
Location (South to North)	% Mortality 2004-2005	% Mortality 2005-2006*	% Mortality 2006-2007*
Blue Earth		46.5	52.3
Waseca		48.6	54.7
Lamberton	47.2	47.3	54.4
Rosemount	48.9	47.8	51.3
Morris		57.9	63.5
Crookston		61.2	72.6
*Model uses mean daily temperature for the period September 21, 2005 to May 1, 2006 and September 21, 2006 to April 23, 2007

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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 Jeanne Ciborowski, 651-201-6217, jeanne.ciborowski@state.mn.us , MDA, 625 Robert St. North, St. Paul, MN 55155. 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/plants/pestmanagement/ipm/ipmnews.htm

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.

Last Revised May, 2007 by woldx018@umn.edu
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