Soybean Aphid Update

Bill Hutchison and Ken Ostlie, Ext. Entomology, Dept. of Entomology, University of Minnesota

As you may have heard from various Midwest Field Crop Newsletters, or the popular press, a new aphid has been causing damage to soybeans, particularly in Wisconsin and Michigan. In Wisconsin, Michigan and northern Illinois, specimens have been identified as Aphis glycines. This is known to transmit many serious virus diseases, such as soybean mosaic, and bean yellow mosaic.

Photo Courtesty of Chris DiFonzo, Michigan State University

Should vegetable growers be concerned? For now, we do not think this should be a problem for Snap, Lima, or Edible bean growers: Where the aphid is confirmed to be A. glycines, this species is only known to feed, long-term, on soybean. It can also overwinter on buckthorn, which has apparently become more common near waterways (in Minnesota). Thus, this aphid should be specific to soybean (and varieties within the Glycine genus); it should not be found on snap bean or dry edible bean (Phaseolus spp. or Vicia fabae).

The important news at this time, is that although aphids have been found on soybean in several Minnesota counties, we do not yet have a confirmation on the identification of these specimens. To date, only one soybean field in Minnesota showed significant yellowing symptoms, that may have been associated with this aphid. However, all other fields have had only very light infestations (e.g., 1-7 aphids/leaflet), with only a few leaves per plant infested.

Without a positive identification, we cannot presently provide specific management recommendations. Dr. David Ragsdale, Entomology, is working with other aphid specialists to provide a positive identification as soon as possible. We will keep you updated as soon as we have more information.

As of August 25, 2000, the most recent MDA Survey Data for Minnesota is available in the "Minnesota Pest Report", now available at: http://www.mda.state.mn.us/pestsurvey/PestReports/PestReport.html
(Click on the link for August 25, 2000)

For more information, and updates regarding the status of this recent aphid invasion, see the Minnesota Web article, Aug. 18, 2000, at: http://www.vegedge.umn.edu/mnvegnew/vol2/818new.htm

Soybean Aphid info. from Wisconsin: http://ipcm.wisc.edu/wcm/00-22insect1.html
Soybean Aphid info. from Michigan: http://www.msue.msu.edu/ipm/CAT00_field/FC08-17-00.htm

Co-Editors: Bill Hutchison, Department of Entomology, University of Minnesota, hutch002@tc.umn.edu
Jeanne Ciborowski, IPM Program, Minnesota Department of Agriculture, jeanne.ciborowski@state.mn.us
Cindy Tong, Department of Horticulture, University of Minnesota, ctong@extension.umn.edu
Production Editor: Suzanne Wold, Research Specialist, University of Minnesota, woldx018@tc.umn.edu

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Last Revised August 25, 2000.
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