MN Fruit & Vegetable IPM News - Vol. 2, No. 15

Fall is a busy time for raspberry, strawberry, and blueberry plants as they store energy for the winter and form flower buds for next spring. Fall is a slow time for strawberry growers because the most important work for the season like weeding, watering, and fertilizing is or almost done.

Perennial weeds, like the berry plants, are still active. They are storing energy in their roots so that they can grow quickly in the spring. Fall is the best time to control some of the most troublesome weeds in the berry patch such as thistle and quackgrass. After frost kills the ragweed, pigweed, and pigeon grass, you will be able to see your perennial weeds preparing for next spring.

Fall is a good time to pull Canada thistles. By pulling them in early fall, you will not kill the plants, but you will weaken their root systems so that they will grow slowly in the spring. Musk thistle became a terrible problem last summer. Musk thistles are a biennial that sprout the first year and bloom the second year. The plants that will bloom next year are in the field now. If you pull musk or bull thistle right now, you will kill the plants.

Fall is the best time to kill quackgrass. If you till quackgrass right before freeze up, the rhizomes at the soil surface will die. If you spray quackgrass with Roundup in late fall, you will kill the plants. You may not see the results this fall but you will next spring. Roundup can be sprayed on quackgrass as late as the middle of November, provided the grass is still green. Grass herbicides like Select and Poast are marginally effective on quackgrass after the middle of September.

Scout any fallow fields that you plan on planting next spring and take all appropriate control measures for thistle and quackgrass. Few herbicides can be sprayed on strawberry plants this time of year. If you spot spray Roundup in a strawberry patch at this time of year, you will have damaged strawberry plants next spring even if you avoid spraying the leaves. The best way of controlling perennial weeds in existing strawberry patches is with leather gloves and good arm strength.

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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, 651-297-3217, 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/

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. ©1999-2005 Minnesota Extension Service, University of Minnesota. All rights reserved. Contact copyright@extension.umn.edu for information on reproduction or use of this material.