WASHINGTON (DTN)--After harvest is an ideal time to test for the presence of soybean cyst nematode (SCN) in fields to be planted with soybeans next year, according to plant pathologists.
"Once infestations are discovered, resistant soybean varieties can be grown to reduce damage and dramatically improve yields," said Iowa State University plant nematologist Greg Tylka. "The key to effective management of SCN is early detection," he reported.
As many as 75% of Iowa fields may harbor the yield-robbing pest; however, SCN usually causes no obvious aboveground symptoms for many years after being introduced into a field, according to Tylka. Consequently, many fields across the Corn Belt that do have SCN have not been diagnosed.
"Soybean fields may be sampled to explain low soybean yields obtained in the 2001 growing season, but cornfields should be sampled this fall in order to detect SCN before next year's growing season," said Tylka.
Soil samples can be collected anytime after harvest, up until the ground freezes solid or is covered with snow. Samples should consist of 10 to 20, 6- to 8-inch-deep soil cores collected from about 20 acres.
Local county extension offices will have information about SCN and in some cases they may provide sampling equipment. Samples can be sent to state or private soil analysis laboratories.