In this Issue:
VEGETABLE NEWS
Review and Recommendations for Late-Season Corn Earworm Control in Sweet Corn—2004
Corn Leaf Aphid Update from Illinois
APPLE NEWS
A Stella is Born: How a Minnesota Apple Grower Developed an Apple of His Own
| Vol 1 No. 12 | August 9, 2004 |
Corn Leaf Aphid Update from Illinois
Rick Weinzierl, University of Illinois (217-333-6651; weinzier@uiuc.edu)
I've had a couple of reports of hard-to-control infestations of corn leaf aphids in northern Illinois sweet corn. While control resulting from the use of malathion and Warrior has been adequate to prevent pollination failures, infestations have persisted and moved from tassels to ear tips, and standards for many fresh-market retail venues make it difficult to sell aphid-infested ears (or ears with lots of “smushed” aphids covering the tips). The key in this problem lies in part in beginning control efforts a little earlier than you would if your only target is corn earworm. As soon as tassels begin to form (or certainly by "row tassel"), if aphids are in the whorl or on the developing tassel, insecticides can provide some degree of control. Malathion was always the old standard for corn leaf aphid control, but it does not persist long (especially in hot weather). Pyrethroids generally are not regarded as especially effective against aphids in most crops, but Capture is better against aphids than most. Given that lots of the state's fresh-market corn sold in farmers' markets is hand-harvested, and given the restrictions on registered insecticides, Capture is probably the best alternative where malathion fails to provide adequate control. Another choice is Lannate, though like malathion, it does not last long in hot weather either. Penncap-M is also labeled for aphid control in sweet corn.
Corn leaf aphids
Editors Note: We have observed a recent increase in corn leaf aphid activity at Rosemount MN, primarily in recently tasseled corn, or where green tassels are just visible within the whorl. For fresh market growers, in particular, it is wise to check ears closely as you near harvest, to assess aphid infestation levels. Based on your markets, a spray (within the appropriate pre-harvest interval) may be needed.
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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
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Last Revised August 5, 2004.
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