• Provide plenty of plant material. When possible send the entire plant, including roots and top growth.
• Provide lots of information, such as a description of the soil, nearby plants, cropping history, pattern of symptoms in the field, and a history of the problem. Remember to include information about chemicals used.
• Include photos when possible.
• Provide freshly collected specimens.
• Be sure the specimen represents the problem.
• Include enough plant material to show all stages of the disease from healthy to very sick.
• Wrap specimens in paper towels or clean news-papers. Do not add moisture. Pack loosely in a plastic bag to reduce drying. Mail in a sturdy container.

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).

Corn smut galls on corn.