In this Issue:
MDA Apple and Strawberry Pest and Identification Manuals
VEGETABLE NEWS
Vegetable Insect Update - Seed Corn Maggot
STRAWBERRY NEWS
Strawberry Insect Pests that will be Monitored in 2005
APPLE NEWS
Apple Insect Pests that will be Monitored in 2005
| Vol 2 No.1 | May 9, 2005 |
Vegetable Insect Update - Seed Corn Maggot
Eric C. Burkness, Suzanne Wold-Burkness, and W.D. Hutchison, Dept. of Entomology, Univ. of Minn.
The peak of the first seedcorn maggot (SCM) flight occurred on April 17 th (342 degree days, lower threshold=39°F) at Rosemount, MN (Dakota Co.). Because the peak has occurred so early this year, even though recent temperatures have been below normal, most crops have not been planted and the risk of SCM damage could be reduced. However, the second generation of SCM still poses a threat to crops that will be planted in the coming weeks. As of May 2, we were at 489 degree days at Rosemount, MN and we would expect the second generation of SCM to peak at 1170 degree days.
We are currently testing SCM lures at Rosemount, MN for use as an early-season monitoring tool. We have caught SCM on the traps, but with the below normal temperatures this past week, SCM activity has been minimal. We will be providing updates on trap catch over the next few weeks.
A few considerations for managing SCM are that seedlings are more susceptible to SCM during a wet, cold spring when seed germination is slowed. The risk for a field developing an SCM infestation should be assessed prior to planting, and appropriate control measures taken, such as the use of insecticidal seed treatments, or in-furrow insecticide applications. Conditions that increase the likelihood of SCM infestations include fields with fresh organic matter, a previous history of SCM infestations, and low-lying or poorly drained areas of the field where germination would be delayed. Once an infestation or damage from SCM has been observed, there is little that can be done to protect the crop.
Besides burrowing into seeds and destroying the germ, SCM damage on snap beans can also include feeding on cotyledons and the first true leaves (see image). The first true leaves may have holes or the maggots may completely eat the leaves, resulting in "snakehead" seedlings (see image). In some cases, the feeding damage completely destroys the growing point. Lab experiments indicate that 5 maggots per snap bean seed cause significant damage. For more information, see the VegEdge fact sheet: http://www.vegedge.umn.edu/VEGPEST/seedmag.htm
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.
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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.