- 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.
This article originally appeared on page 133 of the IC-494(16) -- June 27, 2005 issue.