ISSUE 16 August 24, 2000
SOYBEAN APHID FOUND IN MIDWEST
A new aphid pest feeding on soybeans has been found in the
midwestern states of Michigan, Illinois, Wisconsin, and possibly Minnesota. Other states
neighboring these are likely to have some aphids present as well. Entomologists from
Michigan, Wisconsin and Illinois reported finding aphids in soybeans in late July and
early August. Last week (August 15) it was confirmed that this aphid was the soybean
aphid, Aphis glycines, an aphid native to Asia but never reported from the
United States. The closest unconfirmed detection of the aphid may be in St. Paul and Rosemont, MN which were found by Bill Hutchison, U of M entomologist, and Erik Burkness.
The soybean aphid is yellow-green with black cornicles ("tail-pipes") and a pale colored cauda (tail projection). As with other aphids, the soybean aphid is small, about the size of a pinhead. Nymphs would be smaller.
Though no detections have been made in North Dakota, yet, field inspections are encouraged to determine if they have moved this far west. A suggested protocol for scouting is to sample 15 plants per field with at least 40 paces between plants. Inspect the undersides of leaves in the top and middle of the plants, or the entire plant if you have time. Record the number of plants infested and the relative abundance of aphids:
- light = only a few aphids present
- medium = aphids common on plant
- heavy = plant inundated with aphids
If you find aphids in soybeans, contact Phillip Glogoza at 701-231-7581 in North Dakota and Ken Ostlie, U of M extension entomologist, at 612-624-7436. Information needed is:
- Name and contact information (address, phone)
- location of field (county, township, 1/4 section, or GPS latitude-longitude coordinates)
- Farmer (cooperator) if different from above
- brief description of the infestation
It is reported that this aphid feeds specifically on soybean (plants in the Genus Glycine). It is not expected that this aphid would feed on dry bean varieties (Phaseolus spp.). There are other aphids that may be found on dry beans, specifically the Bean aphid, Aphis fabae. This aphid is blue-black in color. The bean aphid has not been a problem in North Dakota.
Useful Websites, for more updates and info, by state:
MICHIGAN: Article by Dr. Chris DiFonzo, MSU: "Aphids amuck: soybean aphids
discovered in U.S." -
August 17, 2000.
WISCONSIN: Article by Dr. John Wedberg, University of Wisconsin, August 17, 2000
ILLINOIS: Article by Dr. Mike Gray at the University of Illinois, August 16, 2000
MINNESOTA: Article by Ken Ostlie and Bill Hutchison, U of M. New Soybean Pest Appears in the Midwest: Is It in Minnesota?? MN Vegetable IPM Newsletter Vol. 2, No. 15, August 18, 2000
FACT SHEET, Australia (Good photos and references)