Wisconsin soybean growers whose yields were less than they expected this fall may have had problems with the soybean cyst nematode. The only way to know if the nematode is limiting yields is to run a soil test.
Testing can help growers make better planting decisions, according to Ann MacGuidwin, a nematologist at the University of Wisconsin-Madison. A trial in 2001 on a field with moderate nematode populations showed that planting a nematode-resistant soybean variety can yield as much as 24 bushels per acre more than a susceptible variety.
MacGuidwin’s laboratory at the College of Agricultural and Life Sciences in Madison will analyze samples for the soybean cyst nematode. In research supported by the Wisconsin Soybean Marketing Board, she and her coworkers are trying to learn more about the pest so growers can manage it successfully.
The soybean cyst nematode has been identified from 26 counties. Marquette and Dodge counties were recently added to a list that includes Adams, Buffalo, Chippewa, Columbia, Crawford, Dane, Dodge, 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 UW-Madison will test for the nematode. To submit samples to the UW-Madison, send samples to Dr. Ann MacGuidwin, University or Wisconsin-Madison, Room 495 Russell Labs, 1630 Linden Drive, Madison, WI 53706. Soil samples should be submitted with the following information: grower name and address, phone number, field name, and any field cropping history.
For further information on nematode testing at the UW-Madison, please contact Dr. Ann MacGuidwin at (608) 263-6131 or Adam Kaszubowski at (608) 265-1155.