MN Fruit & Vegetable IPM News - Vol. 1, No. 5

This spring, I am helping five strawberry growers throughout Minnesota implement integrated pest management practices that were outlined in the Minnesota Department of Agriculture’s publication: “Integrated Pest Management Manual for Minnesota Strawberry Fields.” Last week I discussed insect management. This week, I will discuss IPM strategies for diseases.

The three major strawberry fruit diseases in Minnesota are gray mold (Botrytis), anthracnose and leather rot. Gray mold and leather rot have been in the state for a long time, but anthracnose is a relatively recent arrival. Most strawberry growers in the state use cultural practices that help control each of these diseases. Straw cover and narrow rows have probably helped people control fruit diseases more than any fungicide on the market.

Each of the growers involved in the project have been assessed as to whether gray mold and anthracnose pose a moderate or severe threat to their harvest, depending on the history of their fields, the vigor of their plants or their location. They have agreed to spray fungicides only under certain climatic conditions. The participants also will establish a spray program that minimizes the threat of the disease developing resistance to fungicides.

For conventional pest control, growers spray strawberries at 10% bloom and 70% bloom. Using integrated pest management, growers monitor the weather and spray when climatic conditions are ripe for the disease to spread. Gray mold needs high humidity, moderate temperatures, and wet conditions during bloom. Anthracnose needs high rainfall, and temperatures above 80°F, after the fruit has formed. Leather rot needs high rainfall. We have installed weather stations at each farm so that the growers can monitor the weather and time their sprays according to climate.

If there is no rain during bloom, then there is no need to spray for gray mold. But after receiving 3 inches of rain during the Memorial Day weekend, most of the growers involved in the project have already sprayed for gray mold.

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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.

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 June 4, 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.