A $10 fee is charged for plant samples. Soil samples (to check for soybean cyst nematode or complete nematode counts, including corn nematodes) cost $15 for Iowa residents and $20 for out-of-state residents. Checks should be made payable to Iowa State University. *When herbicide injury is suspected, the samples should go to the extension weed specialists (see the Weed ID and Herbicide Injury DIagnosis form).