Were your soybean yields low last year? Was the yield low in a field where you didn”t expect it? The problem could be the soybean cyst nematode, a pest that has now been reported from 25 Wisconsin counties.

Last year, University of Wisconsin-Madison trials on soils where nematodes were abundant showed that nematode-resistant soybean varieties yield as much as 23 bushels per acre more than a susceptible variety.

Testing fields for the soybean cyst nematode can help growers make better planting decisions, according to Ann MacGuidwin, a nematologist in the UW-Madison Department of Plant Pathology. A soil test shows the pest”s population density, which is important for deciding whether or not to plant a soybean variety with resistance to the nematode.

The soybean cyst nematode now has been identified from fields in Adams, Buffalo, Chippewa, Columbia, Crawford, Dane, Dunn, Eau Claire, Grant, Jefferson, Juneau, Kenosha, La Crosse, Marquette, Milwaukee, Outagamie, Pepin, Racine, Rock, Sauk, Sheboygan, Trempealeau, Walworth, Washington and Waushara counties.

To collect a soil sample, use a soil probe or hand trowel. Collect 10 to 20 soil cores 6 to 8 inches deep in a zigzag pattern throughout 10 to 20 acres of a field, as done for a soil fertility sample. Dump cores into a bucket and mix thoroughly. After mixing the collected soil, remove about one pint for nematode analysis.

Several private labs and the UW-Madison will test for the soybean cyst nematode. To submit samples to the UW-Madison, send samples to Dr. Ann MacGuidwin, University of Wisconsin-Madison, 495 Russell Labs, 1630 Linden Drive, Madison, WI 53706. The fee for each sample is $10. Please include the following information with each sample: grower name and address, phone number, field name, and any field cropping history.

MacGuidwin”s laboratory at the College of Agricultural and Life Sciences uses the test results to help map the nematode”s distribution in Wisconsin. In research supported by the Wisconsin Soybean Marketing Board, she and her coworkers have begun studies to learn more about the pest so growers can manage it successfully.

For additional information, contact Ann MacGuidwin at (608) 263-6131 or Adam Kaszubowski at (608) 265-1155.