In this Issue:
VEGETABLE NEWS
STRAWBERRY NEWS
Strawberry IPM Update
APPLE NEWS
Excerpt from: When to Prune Out Fire Blight: To Prune or Not to Prune
Weekly Trap Counts: July 11 - July 21, 2005
PLEASE NOTE: The Newsletter will not be published for the next 2 weeks. The next Newsletter will be available on August 12.
| Vol 2 No.11 | July 25, 2005 |
Strawberry IPM Update
Thaddeus McCamant, Specialty Crops Management Specialist, Northland Community & Technical College
Mowing Strawberry Fields
As the 2005 strawberry harvest ends, the 2006 growing season is beginning. From now until October, all the work you do in your fields will benefit next year’s crop. One of the more unusual strawberry growing practices is mowing off all the leaves after harvest. Mowing the leaves off strawberries is an important integrated pest management tool when done correctly.
Reasons to Mow. In a recent study in Denmark, strawberries that were mowed at renovation had a higher yield than unmowed plants the two years the study was conducted. On the second year, mowed plants had significantly larger fruit size as well. Mowing kills many of the runner plants before they root which prevents overcrowding in the row and helps fruit grow larger. Mowing your fields kills all the older, inefficient leaves so that new, healthy leaves can grow. New leaves are healthier and grow quickly in the absence of the older, often diseased leaves. Mowing also breaks the disease cycle of many foliar diseases. Leaf diseases have been terrible this spring. When you mow, you are killing the fungi that cause the disease, and reducing fungal inoculum in your fields. Removing the leaves from the field after mowing may lower the leaf disease pressure even more.
Reasons not to Mow. If the row is thin and needs more plants in order to achieve an adequate yield, you may want to skip mowing or mow very high so that the new runners can peg in and fill in the row. Do not mow after August 1 under any circumstances. Your plants will start producing flower buds about August 15, and you will need a full canopy by the middle of August. If you have a late season, and you are picking on the last week of July, you either have to close the field down early or skip mowing altogether.
Suggestions. If your plants are healthy, you can mow two inches above the crown without causing any damage. If the weather is hot, you may want to mow high enough so that you are leaving enough leaves to shade the crowns. Jewel plants sometimes die during mowing if the weather is hot and dry and they are mowed too short. Always irrigate before you mow, especially in hot dry weather like we are having now.
Grubs are Back
After a four year absence, white grubs are causing problems in berry fields again. Most white grubs are the larvae of the common June beetle (Phyllophaga species). The grubs feed on plant roots and will move down a strawberry row, killing every plant in the row. Plants killed by grubs die suddenly, and have roots that are less than a half inch long. In minor infestations, you will want to dig up plants and kill the grubs.
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.