NEWS for North Dakotans
Agriculture Communication, North Dakota State University
7 Morrill Hall, Fargo, ND 58105-5665
September 7, 2000
A North Dakota State University entomologist is encouraging area soybean producers to scout fields for a new aphid pest that has been found feeding on soybeans in Iowa, Michigan, Illinois, Wisconsin and possibly Minnesota.
The new pest is the soybean aphid, an aphid native to Asia but never before reported in the United States, says Phil Glogoza, extension entomologist at NDSU. The closest, but unconfirmed, detection of the aphid was by a University of Minnesota entomologist near St. Paul.
The soybean aphid is yellow-green with black cornicles ("tail pipes") and a pale colored tail projection. The aphid is small, about the size of a pinhead. Nymphs would be smaller.
Glogoza says reports from Asia indicate that the soybean aphid colonizes tender leaves and branches of soybean plants from the seedling stage to blooming. Later the aphids slow their reproduction rate and move down to the middle and lower part of the plant, where they feed on the undersides of leaves. Toward the end of the season the colonies begin to rapidly increase in size, followed by migration to an alternate host for overwintering.
Reports from entomologists in the states where infestations have been confirmed are reporting similar trends. Observations in the infested states will lead to a better understanding of what the soybean aphid will do in the U.S., says Glogoza.
Although no infestations have been reported in North Dakota, he encourages field inspections to determine if the aphids have moved this far west. He suggests sampling 15 plants per field, with at least 40 paces between plants, inspecting the undersides of leaves in the top and middle of the plants.
If insects that may be soybean aphids are found, Glogoza says to contact him at (701) 231-7581 or, in Minnesota, Ken Ostlie, UM extension entomologist, at (612) 624-7436. Information needed includes the name, address and phone number of the contact, location of the field, name of the farmer (if different), and a brief description of the infestation.
This aphid is reported to feed specifically on soybean plants and is not expected to be found in dry beans.
Source: Phil Glogoza, (701) 231-7581
Editor: Gary Moran, (701) 231-7865