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Corn Leaf Aphid Alert

Order: 2007 Minnesota Vegetable Guide

Insect, Pest Fact Sheets

Corn Leaf Aphid Alert

Eric Burkness, Department of Entomology, University of Minnesota

Recent weather conditions have been favorable for the development of corn leaf aphid populations in sweet corn and we have had reports that populations are present in many fields this year. Yield impact from heavy aphid infestations will be more likely in sweet corn under drought stress. In addition, heavy honeydew production from the aphids can affect pollination and lead to a black mold forming on ears that will affect marketability for fresh market growers.

Corn leaf aphids

The following are basic management guidelines for corn leaf aphid in sweet corn.  If fields are less than 50% pollinated and have at least 50% of the plants infested with at least 50 aphids/plant, then treatment may be warranted. As you scout your fields also take note of beneficial insects such as lady beetle adults and larvae, minute pirate bugs, lacewing larvae, and nabids (see pictures, below). These insects will help reduce or slow down the growth of aphid populations in sweet corn. And remember, Bt sweet corn does not control insect pests other than European corn borer or corn earworm so attention should be paid to aphid and corn rootworm (silk clipping) populations and treatments applied appropriately.

Adult Harmonia axyridis lady beetle on an aphid-infested sweet corn tassel	Lady beetle eggs near an aphid-infested sweet corn tassel
Harmonia axyridis larva on a sweet corn leaf	Lacewing larva feeding on aphids

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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, 651-201-6217, jeanne.ciborowski@state.mn.us , MDA, 625 Robert St. North, St. Paul, MN  55155.  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/plants/pestmanagement/ipm/ipmnews.htm

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.

Last Revised July, 2007 by woldx018@umn.edu
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